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Have you ever wondered why GreenSock doesn't use a more common open source license like MIT? Sometimes our licensing model is misunderstood but hopefully after reading this article you'll see why it is so foundational to the success of our tools and why it ultimately benefits users too. Open source is awesome! If you had to write and maintain your own jQuery or React or GSAP, could you do it? Would it be as refined and reliable? Probably not. How many times have you found a library or chunk of code on github that saved you hours of development time? Open source can be a quick path to great results. It also serves as a jumping-off point for up-and-coming developers to share their innovation, inspiring others to write better code. Open source is easily one of the most influential movements in the entire development community. We're certainly not anti-open-source. Quite the contrary. Open source is *not* always awesome Despite its strengths, there are some dark sides to open source. Many projects are riddled with bugs, poorly documented, and sometimes even dangerous to use. The web is littered with abandoned projects that once seemed promising. It's like a clearance bin you'd find at a discount store; there may be some treasures in there, but you'll have to dig through a lot of undesirables to find the gems. In an industry that's inundated weekly with "hot new" libraries, all just a click away for free, it can be tough to figure out which ones to gamble on. Commitment required(?) Some libraries are one-trick ponies that don't require ongoing commitment. For example, a math library that performs matrix operations or a formatting library. If the author abandons the project, it's no big deal. Other projects, like a full-featured animation library, are much more complex and leverage browser-level optimizations that are moving targets. Vendor-specific bugs need to be worked around or new browser features get introduced that beg to be animated. Plus, animation is the most performance-sensitive aspect of the user experience, so a commitment to ongoing optimization pays dividends. Beyond the code itself, what about community, documentation and examples? These become increasingly important as a library's feature set expands and companies standardize on it, needing to train new staff. Again, some projects have very little need for ongoing support but for GreenSock, it seemed essential. Hampered by success Paradoxically, success is the very thing that kills many open source projects because they don't have a funding mechanism to underwrite all the demands. The project that was once the twinkle in the author's eyes often ends up being a thorn in their side. They can't afford (or don't really want) to keep up with the demands. That's not to say that all open source projects suffer this fate. We have the utmost respect for open source authors, and we don't mean to diminish anyone's hard work or generosity. But there are some common frailties of open source projects in general that GreenSock aims to avoid. Having built and maintained a popular library for over a decade, we've learned that one of the most important factors in keeping a complex project like GSAP vibrant is the licensing model. Our goal was to make GreenSock tools not only accessible (which MIT does a great job of), but also sustainable, business-friendly, consistent, and respectful. We needed a license that would have the best chance of facilitating those goals, as described below: Sustainable Scores of animation libraries have come and gone over the years. We didn't want to be just another flash in the pan that ultimately leaves users feeling abandoned. Trust is paramount for us. We wanted the GreenSock brand to be associated with an exceptionally high level of commitment and reliability. Earning that trust requires a consistent, full-time effort so we considered these funding models: Self-funded - most open source projects are self-funded, meaning that the authors cover all the costs themselves, typically by donating their time and resources. It's noble and perfectly adequate for many projects. An MIT (or similar) license is a great fit because it allows an author to share code with almost zero strings attached. However, the commitment level tends to be unreliable and self-funded projects are rarely sustained long-term. With our particular project and goals, this wasn't a good fit. Corporate sponsorship - sometimes huge companies like Adobe, Microsoft, Facebook, or Google are willing to contribute funds to encourage a project. They usually have a vested interest in its success. For example, Adobe helps fund CreateJS which is a set of libraries that its very own Adobe Animate (formerly Flash) relies on. React is underwritten by Facebook. This can be a great way to offload development costs onto some deep-pocketed corporations, keeping it totally free for end users. The risk, however, is that if the project goals don't line up with the corporation's agenda (which can shift), funding gets yanked or the developers get pressured to go in a direction that may not be good for end users. If the company has a bad year, they may re-allocate resources. The project is ultimately beholden to a few key sponsors with potentially conflicting objectives. This wasn't something we were comfortable with although we acknowledge that it's a great solution for certain projects. Private investors - famo.us is probably the most well-known example of an "open source" project that took on private investors. A few years and $30,000,000+ later, it stopped development of its open source library and laid off a large chunk of its staff, deciding to "pivot" in a more profitable commercial direction. Private investors want a return on their investment (which is completely understandable) but an MIT license can make that very difficult because it leaves the IP (intellectual property) wide open for anyone to steal, including competitors. Similar to corporate sponsorship, projects who get their funding this way are beholden to a few key stakeholders who may have a very different agenda than end users. Again, this wasn't an ideal fit for GreenSock. User-funded - when funding comes directly from end users, it creates a wider base (more stable) and incentivizes the kind of innovation that end users actually care about, otherwise funding naturally dries up. That's a healthy dynamic for aligning agendas. Rather than serving a small set of outside investors looking for a return or a corporation with profit centers to bolster, end users play the central role. The downside, of course, is that certain features or use cases involve a fee. That can be a tough pill to swallow for some, especially when "free" MIT-licensed options abound. And it takes time to build up a wide base of users who literally "buy in". Trust and longevity are key. But a surprising number of users embrace this model because it allows them to "vote" with their dollars and participate in making a product they love continue to thrive. While this model certainly isn't for everyone, it has been a good fit for GreenSock. Accessible Sometimes we hear comments like "you can't use GreenSock in commercial projects without a license." WRONG. [loud buzzer noise]. Our license was designed to make the tools extremely accessible, even permitting usage in one-off commercial projects (where you get paid a one-time fee by a single client). And of course it's free to use in non-commercial projects (see licensing page for details). That way, a certain breed of power-user provides the funding that benefits everyone. An estimated 95%+ of our users never pay us a dime. So while a rare type of commercial project does require a "Business Green" Club GreenSock membership (which covers an unlimited number of projects while active), the vast majority of users never need that special license. This accessibility was a cornerstone of our approach. We didn't want to hide all the tools behind an intimidating paywall or make all commercial uses trigger a fee. Yet it couldn't be as unrestrained as MIT because that would create vulnerabilities for us and our users (as described in this article). Another way we keep the core tools accessible is by freely exposing the raw source code both on github and in our downloads. Users can peek under the hood and see how things work. That makes troubleshooting and learning much easier. We tried to strike a balance of openness and healthy insulation from the frailties of MIT. Business-friendly Most businesses are very concerned about IP infringement, lawsuits, and indemnification. The "no strings attached and no warranties" nature of MIT is both a strength and a weakness. It simplifies sharing, but what if an open source library leverages someone else's IP? What if it uses "copyleft" code that infects anything it touches, requiring that all projects using it be open-sourced as well? That could be a huge problem for businesses with proprietary tools in a competitive market. GreenSock's license doesn't have any attribution requirements, nor does it impose share-alike rules like GNU and Creative Commons. Furthermore, it contains warranties that aren't found in MIT-like licenses, making GreenSock more business-friendly. It survived the software audits and legal review process at reputable companies like Google, Sony, EA, Intel, every major ad network, and many others. This vetting is necessary in the business world where there is so much at stake. The license also allows for code edits to be made for bug fixes. Typically that's not necessary because we handle it as a part of our ongoing support efforts, but businesses appreciate knowing that if we relaxed those efforts, they'd still be able to get their project working if they ran into a bug and needed to squash it themselves. Consistent MIT-licensed projects spread on github where it's trivial to fork them and start making custom flavors. That's ideal for authors whose goal is to start something and then step back to let the community run with it. But that can lead to a lot of confusion as different flavors start popping up with incongruent feature sets and incompatibilities. Focus and direction are easily lost. If there's no driver (or too many drivers), it can be a scary ride for the passengers. We wanted the GreenSock brand to convey a certain level of consistency and reliability. That's part of the reason we don't generally accept pull requests - we keep a tight reign on the codebase so that we are intimately aware of every piece. That allows us to not only support it, but also stand behind our IP warranties. Respectful We believe that if we respect our users, they'll generally reciprocate that respect. Most people want to do the right thing. So we don't inject "phone home" code that reports usage or causes things to suddenly stop working when a membership expires. We don't force business customers register each user or enter serial numbers to activate seats. We don't limit installations or the number of projects that the license covers. We don't burn extra energy policing usage. We've never sued anyone. We funnel our energy into refining the tools, innovating, educating, and supporting our users. We put a lot of effort into creating a positive, respectful culture in the forums which boast over 50,000 members and 80,000 posts. We don't charge a dime for support there, and we don't shamelessly promote Club GreenSock memberships. Again, we trust that if we keep trying to provide value, people will notice and gladly sign up to support the efforts at some point. An unintended benefit of our licensing model has been that it naturally weeds out users who expect everything for free and don't recognize the substantial effort that goes into these projects. We're left with users who tend to be very respectful and trustworthy (exactly who we like to serve). Conclusion GreenSock isn't the typical open source project. Our licensing model reflects that. It offers a blend of sustainability, accessibility, business-friendliness, consistency, and respect that'd be very difficult (or impossible) to accomplish with an MIT-like license. It's not necessarily "better" (open source is fantastic, really) but in our particular case it aligned more closely with the project goals. In fact, many companies have chosen GreenSock because of the license, not in spite of it. They wanted to invest in a platform that had a certain level of commitment behind it that's rare in the open source world. After a decade, the experiment seems to be working and we have our supporters to thank for that. We've been humbled and inspired by Club GreenSock members throughout the years. It's a privilege to create these tools and serve the community. We're grateful for their partnership which makes it all possible.

Note: This page was created for GSAP version 2. We have since released GSAP 3 with many improvements. While it is backward compatible with most GSAP 2 features, some parts may need to be updated to work properly. Please see the GSAP 3 release notes for details. Here are some of the highlights of the GSAP 1.20.0 release... yoyoEase Now you can specify an ease for the yoyo (backwards) portion of a repeating TweenMax animation. Set it to a specific ease like yoyoEase:Power2.easeOut or to flip the existing ease, use the shortcut yoyoEase:true. TweenMax is smart enough to automatically set yoyo:true if you define a yoyoEase, so there's less code for you to write. Score! Animate CSS Variables (custom properties) See the Pen CSS Variables Demo by GreenSock (@GreenSock) on CodePen. Emoji support in TextPlugin 'Nuf said. ...and more There are quite a few little improvements and bug fixes as well, which are listed in the changelog at the github repository. Download GSAP today. Happy tweening!

Note: This page was created for GSAP version 2. We have since released GSAP 3 with many improvements. While it is backward compatible with most GSAP 2 features, some parts may need to be updated to work properly. Please see the GSAP 3 release notes for details. Club GreenSock members get a fresh batch of superpowers with updates to SplitText and ScrambleText, plus two brand new customizable eases in this 1st-Quarter 2017 update! It's our way of saying "thanks" to those who support our ongoing efforts. Let's dig right into the upgrades... SplitText SplitText now supports nested tags like <span>, <strong>, <em>, <p>, etc. This means you can split text with various styling and even links. To make things even cooler, SplitText now supports emoji characters ! SplitText demo See the Pen BzmGba by GreenSock (@GreenSock) on CodePen. "Simply Green" gets ScrambleText We moved ScrambleText into "Simply Green" membership level to deliver even more value. NEW: CustomWiggle and CustomBounce Add wiggle and bounce effects to your GSAP animations with these brand new, highly customizable eases. Even get squash and stretch! CustomWiggle and CustomBounce are now included for anyone with a "Shocking Green" or "Business Green" membership. To learn more visit greensock.com/wiggle-bounce. Thanks We're incredibly grateful to each and every Club GreenSock member, as we simply couldn't do what we do without your ongoing support. It's a privilege to have such a top-notch community around GSAP. Please feel free to plug in even more by participating in the forums to help others or to get your questions answered. It's a fantastic place to learn and be inspired. Enjoy the fresh updates, and happy tweening! [loginwidget]

Note: This page was created for GSAP version 2. We have since released GSAP 3 with many improvements. While it is backward compatible with most GSAP 2 features, some parts may need to be updated to work properly. Please see the GSAP 3 release notes for details. Are your animations meant to feel playful? Robotic? Slick? Realistic? If they had a voice, what would they sound like? To become an animation rock star, you must develop a keen sense of easing because that's what determines the style of movement between point A and point B. GreenSock's new CustomEase frees you from the limitations of canned easing options. Create literally any ease imaginable. Zero limitations. CSS animations and WAAPI offer cubic-bezier() which is great but with only two control points it's impossible to create more complex effects like bouncing, elastic, wiggles, rough/jerky eases, etc. Plus you can't make an ease return to its starting values (like a ball jumping into the air and falling back to the ground with a bounce). Features Unlimited anchors and control points. Copy/Paste any SVG <path> (including direct copy/paste from Adobe Illustrator). Use CSS cubic-bezier() values (For example, from cubic-bezier.com). Editor has snapping, undo, sample code and other conveniences. Start with any standard ease and customize it. getSVGData() method turns any ease into SVG <path> data for display at the size you define. Extremely optimized for runtime performance. Free for anyone with a GreenSock account. Reading Ease Curves, Editing, and Using CustomEase Here's an in-depth video tour that'll get you up to speed with exactly how to use CustomEase: Ready to play? Check out the new Ease Visualizer with CustomEase support. Click "Custom" to edit the curve as much as you want: Simple Example See the Pen Video: Single Tween with CustomEase by GreenSock (@GreenSock) on CodePen.&#13;We strongly recommend creating your CustomEases initially (rather than in each tween) to maximize performance and readability. You then reference them by ID in your tweening code. When an ease is created, it must parse through the points and do various calculations to prepare for blisteringly fast runtime performance during the animation, so executing those calculations when your page/app loads is typically best. Download CustomEase To get CustomEase, you must have a GreenSock account which is completely free to set up. Plus it gets you access to our community forums (a fantastic place to learn and get your questions answered). The widget below lets you sign up or if you're already logged in, it'll give you immediate access to the download zip that contains CustomEase in the "easing" directory. Note: CustomEase is not in the github repository or CDN; it's only available for download at GreenSock.com. [loginwidget]

Note: This page was created for GSAP version 2. We have since released GSAP 3 with many improvements. While it is backward compatible with most GSAP 2 features, some parts may need to be updated to work properly. Please see the GSAP 3 release notes for details. GSAP version 1.19.0 introduces some exciting new features for advanced users as well as conveniences for everyone (even the "greenest" novices). The most noteworthy improvements are summarized below: Function-based values Instead of a number (x:100) or string (width:"300px") or relative value (y:"+=50"), you can now define most values as a function that'll get called once for each target the first time the tween renders, and whatever is returned by that function will be used as the value. This can be very useful for randomizing things or applying conditional logic. See it in action in the demos below. See the Pen BzmGba by GreenSock (@GreenSock) on CodePen. ...and more GSAP 1.19.0 is more ES6-friendly (for example, you can npm install gsap and then import {TweenLite, Elastic, TimelineMax} from "gsap" in your project). Plenty of bug fixes too. See the whole list in the github changelog. DOWNLOAD GSAP TODAY Happy tweening!

Note: This page was created for GSAP version 2. We have since released GSAP 3 with many improvements. While it is backward compatible with most GSAP 2 features, some parts may need to be updated to work properly. Please see the GSAP 3 release notes for details. Since launching MorphSVGPlugin, we've made a bunch of improvements and exposed several new features. Here are the highlights... The challenge Before we dive into solutions, it helps to understand the tasks that MorphSVGPlugin must perform in order to work its magic: Convert the path data string into pure cubic Beziers Map all of the segments between the start and end shapes (match them up), typically based on size and position If there are more segments in one than the other, fabricate new segments and place them appropriately Subdivide any segments with mis-matching point quantities If a shapeIndex number isn't defined, locate the one that delivers the smoothest interpolation (shortest overall distance that points must travel). This involves looping through all the anchor points and comparing distances. Convert all the data back into a string Isolate the points that need to animate/change and organize a data structure to optimize processing during the tween. That may sound like a lot of work (and it is) but MorphSVGPlugin usually rips through it with blazing speed. However, if you've got a particularly complex path, you'll appreciate the recent improvements and the new advanced options: Performance tip #1: define a shapeIndex MorphSVGPlugin's default shapeIndex:"auto" does a bunch of calculations to reorganize the points so that they match up in a natural way but if you define a numeric shapeIndex (like shapeIndex:5) it skips those calculations. Each segment inside a path needs a shapeIndex, so multiple values are passed in an array like shapeIndex:[5,1,-8,2]. But how would you know what numbers to pass in? The findShapeIndex() tool helps for single-segment paths, what about multi-segment paths? It's a pretty complex thing to provide a GUI for. Typically the default "auto" mode works great but the goal here is to avoid the calculations, so there is a new "log" value that will act just like "auto" but it will also console.log() the shapeIndex value(s). That way, you can run the tween in the browser once and look in your console and see the numbers that "auto" mode would produce. Then it's simply a matter of copying and pasting that value into your tween where "log" was previously. For example: TweenMax.to("#id", 1, {morphSVG:{shape:"#otherID", shapeIndex:"log"}}); //logs a value like "shapeIndex:[3]" //now you can grab the value from the console and drop it in... TweenMax.to("#id", 1, {morphSVG:{shape:"#otherID", shapeIndex:[3]}}); Notes shapeIndex:"log" was added in MorphSVGPlugin version 0.8.1. A single segment value can be defined as a number or a single-element array, like shapeIndex:3 or shapeIndex:[3] (both produce identical results) Any segments that don't have a shapeIndex defined will always use "auto" by default. For example, if you morph a 5-segment path and use shapeIndex:2, it will use 2 for the first segment and "auto" for the other four. Performance tip #2: precompile The biggest performance improvement comes from precompiling which involves having MorphSVGPlugin run all of its initial calculations listed above and then spit out an array with the transformed strings, logging them to the console where you can copy and paste them back into your tween. That way, when the tween begins it can just grab all the values directly instead of doing expensive calculations. For example: TweenMax.to("#id", 1, {morphSVG:{shape:"#otherID", precompile:"log"}}); //logs a value like precompile:["M0,0 C100,200 120,500 300,145 34,245 560,46","M0,0 C200,300 100,400 230,400 100,456 400,300"] //now you can grab the value from the console and drop it in... TweenMax.to("#id", 1, {morphSVG:{shape:"#otherID", precompile:["M0,0 C100,200 120,500 300,145 34,245 560,46","M0,0 C200,300 100,400 230,400 100,456 400,300"]}}); As an example, here's a really cool codepen by Dave Rupert before it was precompiled: http://codepen.io/davatron5000/pen/meNOqK/. Notice the very first time you click the toggle button, it may seem to jerk a bit because the entire brain is one path with many segments, and it must get matched up with all the letters and figure out the shapeIndex for each (expensive). By contrast, here's a fork of that pen that has precompile enabled: http://codepen.io/GreenSock/pen/MKevzM. You may noticed that it starts more smoothly. Notes precompile was added in MorphSVGPlugin version 0.8.1. Precompiling only improves the performance of the first (most expensive) render. If your entire morph is janky throughout the tween, it most likely has nothing to do with GSAP; your SVG may be too complex for the browser to render fast enough. In other words, the bottleneck is probably the browser's graphics rendering routines. Unfortunately, there's nothing GSAP can do about that and you'll need to simplify your SVG artwork and/or reduce the size at which it is displayed. The precompiled values are inclusive of shapeIndex adjustments. In other words, shapeIndex gets baked in. In most cases, you probably don't need to precompile; it's intended to be an advanced technique for squeezing every ounce of performance out of a very complex morph. If you alter the original start or end shape/artwork, make sure you precomple again so that the values reflect your changes. Better segment matching In version 0.8.1, there were several improvements made to the algorithm that matches up corresponding segments in the start and end shapes so that things just look more natural. So even without changing any of your code, loading the latest version may instantly make things match up better. map: "size" | "position" | "complexity" If the sub-segments inside your path aren't matching up the way you hoped between the start and end shapes, you can use the map special property to tell MorphSVGPlugin which algorithm to prioritize: "size" (the default) - attempts to match segments based on their overall size. If multiple segments are close in size, it'll use positional data to match them. This mode typically gives the most intuitive morphs. "position" - matches mostly based on position. "complexity" - matches purely based on the quantity of anchor points. This is the fastest algorithm and it can be used to "trick" things to match up by manually adding anchors in your SVG authoring tool so that the pieces that you want matched up contain the same number of anchors (though that's completely optional). TweenMax.to("#id", 1, {morphSVG:{shape:"#otherID", map:"complexity"}}); Notes map is completely optional. Typically the default mode works great. If none of the map modes get the segments to match up the way you want, it's probabaly best to just split your path into multiple paths and morph each one. That way, you get total control. Animate along an SVG path The new MorphSVGPlugin.pathDataToBezier() method converts SVG <path> data into an array of cubic Bezier points that can be fed directly into a BezierPlugin-based tween so that you can essentially use it as a motion guide. Watch the video Demo See the Pen pathDataToBezier() docs official by GreenSock (@GreenSock) on CodePen. Morph back to the original shape anytime If you morph a path into various other shapes, and then you want to morph it back to its original shape, it required saving the original path data as a variable and feeding it back in later. Not anymore. MorphSVGPlugin records the original path data in a "data-original" attribute directly on the element itself, and then if you use that element as the "shape" target, it will automatically grab the data from there. For example: TweenMax.to("#circle", 1, {morphSVG:"#hippo"}); //morphs to hippo TweenMax.to("#circle", 1, {morphSVG:"#camel"}); //morphs to camel TweenMax.to("#circle", 1, {morphSVG:"#circle"}); //morphs back to circle. Conclusion We continue to be amazed by the response to MorphSVGPlugin and the creative ways we see people using it. Hopefully these new features make it even more useful. How do I get MorphSVGPlugin? If you're a "Shockingly Green" or "Business Green" Club GreenSock member, just download the zip from your account dashboard or the download overlay on GSAP-related page on this site. If you haven't signed up for Club GreenSock yet, treat yourself today.

Note: This page was created for GSAP version 2. We have since released GSAP 3 with many improvements including a much smaller file size! Please see the GSAP 3 release notes for details. In recent months, the whirlwind shift to HTML5 in the banner ad industry has prompted a slew of policy changes. Publishers and networks are scrambling to answer questions from designers who want to build things "properly" (a term whose meaning can vary wildly these days). Growing pains abound. Shortly after we published an article describing the state of affairs and offering recommendations for a path forward, the IAB released a draft of their new HTML5 ad specs which echoed many of those recommendations. For example, the file size limit for standard ads was raised to 200kb. This was cause for much celebration across the industry. But we're not out of the woods yet. There is still a persistent mindset about how we look at kilobytes that's crippling the web. This article aims to challenge the old paradigm and explain why it's so important to re-assess kilobyte costs. Why limit kilobytes? Conventional wisdom says that kilobytes have a direct impact on load times and consequently user experience. File size limits exist to promote better performance. Period. Does conventional wisdom apply the same way in the HTML5 era? As we modernize our kilobyte-count policies, let's remember what the goal is: performance...or more accurately, better user experience. Not all kilobytes are created equal HTML5 has unique strengths that challenge us to move beyond the simplistic "aggregate total file size" mentality of yesteryear. We need to look at kilobyte cost in a new, more nuanced way. There are four primary factors: Cache status When is 35kb not really 35kb? When it's cached. A cached file has absolutely zero bandwidth cost regardless of its size. It loads immediately. This is particularly relevant in banner ads because there are certain chores common to almost every ad (like animation management tasks) that can be encapsulated and shared among many, many banners. The end user only loads that shared resource once and then it's cached and completely "free" thereafter...for all ads pointing at that file...on all sites. Does it really make sense to penalize ads for using those ubiquitous shared resources even though they're so pervasively cached that they don't typically affect load performance? In the modern world, file size limits should apply to the banner-specific assets that have a direct impact on loading times, not standardized shared resources. Location Kilobytes loaded from a CDN (Content Delivery Network) are typically "faster" because they're geographically dispersed and automatically loaded from the closest server. Plus CDNs have inherent redundancies leading to better reliability. Spread 200kb spread across 24 files will take longer to download than 200kb spread across only 4 files. This isn't particularly relevant in the discussion about shared resources (which should be cached very quickly), but is an argument in favor of loading TweenMax rather than the combination of TweenLite, CSSPlugin, EasePack, and TimelineLite even though they collectively use fewer kilobytes. If the industry remains focused solely on aggregate total file size, it pushes designers/developers toward less capable solutions that use fewer kilobytes even though they don't necessarily affect load times and could be replaced by more robust options that allow more creative expression. Performance yield Some kilobytes are cheap in terms of the initial load but expensive for runtime execution. If our goal is better user experience, this factor should weigh heavily into the overall kilobyte cost equation. Would you rather have a banner that loads 200ms faster with janky animation or one that's super-smooth at runtime but takes a fraction of a second longer to load? Are publishers primarily concerned with displaying ads faster initially or ensuring that their site runs smoothly once loaded? Of course there are reasonable limits either way (waiting an extra 30 seconds for a huge file to load would be intolerable even if it made things run buttery smooth), but in most cases we're only talking about fractions of a second difference. For example, GSAP contains "extra" code that automatically GPU-accelerates transforms, applies lag smoothing, leverages 3D transform matrices, avoids layout thrashing, organizes things internally to make auto overwriting super fast, etc. - would removing those features for the sake of milliseconds on initial load (and zero savings once it's cached) be a step forward or backward? Incentivizing the wrong things If the IAB and publishers don't embrace a common set of shared resources that get excluded from file size calculations... It creates inefficiencies and redundancies - thousands of ads may each contain their own [duplicate] copy of a library like TweenMax, squandering valuable bandwidth. It penalizes the use of robust, industry-standard libraries in favor of custom JS and micro-libraries that probably aren't nearly as capable, well-tested, cached, compatible, or performant. When something breaks, it will be more difficult for the various ad networks and publishers to troubleshoot and support custom JS and diverse micro-libraries. Lots of APIs to learn (or in the case of custom JS, more advanced expertise would be required). GreenSock would likely need to create a minimalistic version of TweenMax that has a tiny subset of the features. We feel strongly that this is a step backward and explain why here. So ultimately, an "all-inclusive" file size policy could actually hurt load times as well as runtime performance. Yet the primary goal of file size limits is to protect performance. Hm. If the industry rallies behind a few popular, well-maintained and performant libraries, exempting them from file size calculations because of their ubiquity, it would not only deliver a better overall user experience, but also make it easier to create high quality banners. There would be fewer headaches for networks and publishers too. TweenMax (GSAP's largest file) technically weighs around 34kb but those kilobytes are the remarkably inexpensive kind. TweenMax is widely cached, it's on multiple CDNs, it packs various tools into a single file (zero "spread"), and it has an extremely high performance yield because of its many runtime performance optimizations. There are so many ads using it already that it has little or no effect on load times. Should it really cost banner ad designers/developers 34kb against their file size budgets? Is it wise to incentivize cooking up their own custom code for handling animation tasks instead? The good news Every major ad network we’ve contacted understands the value of shared resources and is very GSAP-friendly. In fact, virtually all of them have GSAP on their own CDNs and don't count its file size against ads unless the publisher insists otherwise (which is rare). One notable exception is Adwords, but we have been told they're working on a solution. Allows GSAP Excludes GSAP from file size calculation* Hosts GSAP on CDN Advertising.com/AOL YES YES YES Google DoubleClick YES YES YES Flashtalking YES YES YES Sizmek YES YES YES Flite YES YES YES Cofactor YES YES YES Adwords YES YES YES *Unless publisher objects which is uncommon Google DoubleClick is even pioneering a process that will automatically detect when GSAP is used in an ad and swap in its own CDN link to maximize caching benefits. Pretty cool stuff. Conclusion Let's embrace the unique strengths of HTML5 and modernize the way we count kilobyte costs. Let's support policies that incentivize better performance and user experience rather than a race to the smallest total file size for each individual ad. Caching, CDNs, kilobyte spread, and performance yield should all factor into the way we view kilobytes the HTML5 era. FAQ Isn't it unfair if the IAB only recommends a few popular libraries? What about newer or lesser-known libraries? This is an entirely valid concern. The list should be reviewed regularly and the IAB can assess each library's industry support, performance profile, compatibility, and track record for ongoing updates and bug fixes. New contenders could be submitted for consideration anytime. But remember that the key to realizing the performance benefits is keeping the list short so that caching is focused and pervasive. If there are too many "standardized" libraries, it dilutes caching and defeats the purpose. There's no way that everyone will agree on which libraries should be on the list but if we get hung up on not offending anyone or being afraid to appear biased, we'll miss the opportunity to move the industry forward. The list won't be perfect, but not having a list at all is much worse. What happens when a library gets updated? Wouldn't it need to be re-cached? Yes. And trust me - we want libraries to be updated somewhat regularly to work around new browser inconsistencies, patch library bugs, and implement new features that drive things forward. But these updates wouldn't need to interfere with existing or legacy ads - when a library is updated, a new CDN URL would be generated and new ads could optionally point to that version. Those ads would indeed trigger browsers to cache that new version but this should happen very quickly. Most likely within a matter of days the new version would be pervasively cached across the web. Yes, each end user would pay that kilobyte tax once on the first load and then it would be "free" thereafter. Would GreenSock still recommend this policy if GSAP wasn't included in the short list of exempt libraries? Absolutely. This isn't just about getting GSAP an exemption - this is what we believe is best for the industry overall even if GSAP isn't on the list.

Note: This page was created for GSAP version 2. We have since released GSAP 3 with many improvements. While it is backward compatible with most GSAP 2 features, some parts may need to be updated to work properly. Please see the GSAP 3 release notes for details. The latest version of GSAP delivers some fun new features that open up entirely new animation possibilities. Check out the videos and demos below that show what's so exciting about 1.18.0. Here's a quick summary: New "cycle" property allows you to add rich variations to staggered animations Relative HSL color tweens (affect just the hue, saturation or lightness) Complex string tweening like "1px 5px rgb(255,0,0)" Numerous improvements and bug fixes (see github) New "cycle" property for staggered animations Have you ever wanted to animate a bunch of elements/targets and alternate between certain values (or even randomize them) in a staggered fashion? The new super-flexible "cycle" property does exactly that. Instead of defining a single value (like x:100, rotation:90), you can define an Array of values to cycle through (like cycle:{x:[100,-100], rotation:[30,60,90]}) or even use function-based values (like cycle:{x:function() { return Math.random() * 200; }}). The amount of functionality you can pack into a single line of code is staggering (pun intended). Demo: array-based and function-based "cycle" values See the Pen Basic staggerTo() using cycle by GreenSock (@GreenSock) on CodePen. Advanced "cycle" effects with SplitText See the Pen SplitText with stagger and cycle by GreenSock (@GreenSock) on CodePen. Caveats The cycle property is available only in the staggerTo(), staggerFrom(), and staggerFromTo() methods in TweenMax, TimelineLite and TimelineMax. When using function-based values the function will be passed an argument which represents the index of the current tween. Inside the function body, the scope (this) refers to the target of the current tween (see source of first demo above). Relative HSL color animation Have you ever wanted to tween a color to something a little darker or lighter without having to guess at cryptic hex values? How about tween a hue to 180 degrees around the color wheel? With relative HSL tweening, it's easy. You can now use familiar relative prefixes ("+=" and "-=") directly inside hsl() strings! //30% darker backgroundColor:"hsl(+=0, +=0%, -=30%)" //to grayscale (0% saturation) backgroundColor:"hsl(+=0, 0%, +=0%)" //opposite color (180 degrees around the other side of the color wheel) backgroundColor:"hsl(+=180, +=0%, +=0%)" Relative HSL demo See the Pen Relative HSL color tweening in GSAP 1.18.0 by GreenSock (@GreenSock) on CodePen. Caveats Be careful about doing relative tweens when they could be interrupted. For example, if you have a mouseover that creates tween to +=30% and then a mouseout that does -=30% and then the user rolls over/out/over/out, you'll get odd results because of the nature of relativity. For bullet-proof rollover effects with relative values check out the demo we used in the video: Hover Demo with Relative HSL Values When you tween to a saturation of 0%, that basically loses any kind of hue data - the underlying color/hue of grayscale is non-existent. So then if you try tweening back to a saturation of 80% or something, it'll be red because that's the default zero position of hue. For example, tween a blue <div> to "hsl(+=0, 0%, +=0%)" and then to "hsl(+=0, 80%, +=0%)", it'll end up red instead of blue. That's not a bug - it's just the nature of colors in the browser (they end up in the rgb color space). Tween complex string-based values Complex string-based values containing multiple numbers can be animated without any extra plugins. For example, a value like "10px 20px 50px" can be animated to "4px 13px 200px". GSAP will find each number in the strings (in order), compare them and animate the ones that changed. CSSPlugin already does this for CSS values and it even converts units, but the base engine (TweenLite) can now do basic string tweening. It will even find rgba(...) values and make sure to round them appropriately during animation. This new feature extends to AttrPlugin too which means it can animate the complex strings inside SVG element attributes like the points in a <polygon> or <polyline> or even <path> data (please carefully read the caveats below). See the Pen Complex string-based tweening: simple shape morph by GreenSock (@GreenSock) on CodePen. Caveats This feature is NOT intended to perform complex shape morphing in SVG. It simply animates the numbers inside the strings (in order). Robust shape morphing requires dynamically parsing path data and injecting extra points in certain cases. This new complex string-based tweening lays the groundwork in the core to do a lot of advanced effects in the future, especially via plugins. If you're animating the "d" attribute of a <path> element or the "points" attribute of a <polygon> or <polyline> element, keep in mind that you MUST make sure the number (and type) of points match between the starting and ending values. And since those are attributes, use the AttrPlugin (which is already inside TweenMax). Community Demos City Construction by Sarah Drasner See the Pen City Construction Site by Sarah Drasner (@sdras) on CodePen. GreenSock Cycle by Petr Tichy See the Pen GreenSock - staggerTo with cycle by GreenSock (@GreenSock) on CodePen. Special Thanks This major update is extra special as it contains features that were largely shaped by feature requests and feedback from our community. We really appreciate the strong community that we have in our forums that not only helps each other, but also helps shape the tools themselves. Extra special thanks to Elliot Geno for suggesting cycle and relative HSL tweening, Diaco for being a testing powerhouse, and everyone who voted on the API changes. Now go download GSAP 1.18.0 and make something beautiful.

Note: This page was created for GSAP version 2. We have since released GSAP 3 with many improvements. While it is backward compatible with most GSAP 2 features, some parts may need to be updated to work properly. Please see the GSAP 3 release notes for details. Published: 2015-08-07 Google sparked an urgent and rather violent shift away from Flash technology when it announced that Chrome will pause "less important" Flash content starting as early as September 2015. Flash has served as the de facto standard for banner ads for more than a decade. Firefox also blocked Flash after major security issues were discovered and Facebook's security chief called for Adobe to kill Flash once and for all. Amazon says it will no longer accept any Flash ads after September 1. Clearly Flash is on its way out of web browsers. Advertisers can no longer afford its liabilities. Now what? Modern browsers are remarkably capable of handling slick animations natively using HTML, JavaScript, and CSS (collectively referred to as “HTML5” or just “H5”), making them the obvious choice as the tag-team successor to Flash. No more plugins. However, a few barriers are clogging up the transition. Some are technical, some are political, and some have to do with a glaring lack of information. Let's address things head-on, identify some solutions, and get things moving in the right direction. GreenSock has a rich heritage in the banner ad industry, serving as its most popular animation library in both Flash and HTML5. In fact, it’s one of the fastest-growing JavaScript tools on the entire Internet and it was originally born out of banner-specific needs. We obsess about animation in the browser, studying the technical challenges, performance benchmarks, and workflow. Consequently, we’re in a unique position to lend a hand during this transition and perhaps illuminate the path forward. 40 kilobytes? Are you kidding? Years ago, when bandwidth was a tiny fraction of what it is today, the ad industry codified a set of standards for banner ad file sizes. A common limit was 40kb (sometimes even 30kb) including all images, fonts, animations and scripts which Flash compressed into a single amazingly small swf file. Technically each publisher determines its own file size policies, but almost everyone looks to the IAB (Interactive Advertising Bureau) as a standards-setting body, like the W3C for web browsers. The IAB exists to help guide the industry but they don't mandate or enforce anything. When Flash ruled the banner ad landscape, certain file size specs were recommended by the IAB and the system worked well. However, the technology landscape has changed drastically. Bandwidth, page size, and banner budget over the yearsBandwidth (Mbps)Banner budget (kb)Page size (kb)2008200920102011201220132014201540kb33Mbps40kb1,795kb Year Bandwidth (Mbps) Banner budget (kb) Page size (kb) Jan 1, 2008 5.86 40 312 Jan 1, 2009 6.98 40 507 Jan 1, 2010 9.54 40 679 Jan 1, 2011 10.43 40 788 Jan 1, 2012 12.7 40 1081 Jan 1, 2013 15.62 40 1529 Jan 1, 2014 20.83 40 1622 Jan 1, 2015 32.78 40 1795 Page size (kb) Since 2008, average bandwidth has grown by a factor of 5.6 which is remarkably on-pace with the growth of the average web page size (5.7), but the IAB has been cautious about declaring HTML5 specs due to all the complexities involved. They released a set of HTML5 guidelines in 2013, but omitted any file size specs, saying only that HTML5 ads weigh "more" than swf ads. Without specs, many publishers clung to the safe limits of yesteryear. The gatekeepers who impose the 40kb budgets often do not have the authority or wherewithal to allow more than what the latest IAB spec dictates. Consequently, developers are forced to shoehorn HTML5 banners into archaic Flash specs which isn't what the IAB intended. This must change. From our vantage point, fear is driving the industry. Publishers and networks are afraid to raise the file size limits without IAB approval. Some do it anyway, but disagree on exactly how much, leading to wild variations. Developers have no choice but to build for the least common denominator in their ad campaign which is either totally unclear or ends up being the dreaded creativity-crushing 40kb. (UPDATE: The IAB released a draft of its new HTML5 specs.) HTML5 is fundamentally different...embrace that HTML5 banners often weigh 3-5 times as much as a Flash swf but far too many people myopically focus on the aggregate total file size. They miss the unique strengths of HTML5 technology that we should be exploiting - shared resources and browser caching. These have a tremendous impact on loading time and overall performance which is the whole point of the file size limits anyway! Flash compiled all assets into a single swf meaning that if 10 different banners on a site all used a certain library, it got baked into each and every swf. End users paid the file size price 10 times. Multiply that by millions of ads and it gets pretty crazy. In HTML5, however, a library can be dropped onto a CDN (content delivery network) and shared among all banners, thus end users only load it once and it’s completely "free" thereafter...for all ads pointing at that CDN...on all sites. This is a BIG deal. It means that common animation chores like the requestAnimationFrame loop, timing, sequencing, intelligent GPU layerizing, lag smoothing, compatibility workarounds, performance optimization, etc. can be extracted and shared among them all (much like what the Flash Player did for swf files). The unique banner-specific code can be much more concise, reducing overall load times and improving performance. File size limitations should be applied to the banner-specific assets, excluding the shared resources that drive common functionality. Imagine how silly it would have been if the 17MB Flash Player download was included in the aggregate file size for each swf banner. Ad networks and publishers can put a certain subset of tested-and-approved libraries onto their CDNs and exempt them from file size calculations. We're thrilled to see industry leaders like Advertising.com/AOL, Google DoubleClick, Flashtalking, and Sizmek already taking this approach with GSAP. This strategy allows developers to avoid burning hours manually cooking up their own proprietary libraries to fit within the ad specs. Ad networks and publishers win because load times (and costs) are lowered and it's easier to troubleshoot problems when a common toolset is used. They reap the benefits of all the compatibility and performance optimizations in tools like GSAP. End users get ads that perform better, load faster, and look more appealing. Animation technologies and approaches For those tasked with building HTML5 banners, the choices are perplexing. Is it best to use a visual IDE like Adobe Edge Animate, Google Web Designer, or Tumult Hype? Even Flash is capable of outputting HTML5 content. These tools can make building ads easier (especially for designers who don’t want to write code), but a common complaint is that the resulting output is bloated and slow, making them ill-suited for banner ads. Some networks explicitly state that they won't accept ads built with these tools. We'd love to see the visual tools mature and export concise, performant, ad-friendly code because plenty of designers aren't comfortable hand-coding banners yet. Ideally, they'd tap into GSAP under the hood so that designers and developers could collaborate on the same files without worrying about runtime redundancies. There are also network-specific banner-building tools but their proprietary nature makes them impractical for many campaigns. If an agency uses one network’s proprietary tool and then their client asks to run the ad on another network too, it must be rebuilt. Learning how to use each network's proprietary tool can be cumbersome. Hand-coded animations are usually much lighter-weight, performant, and universally accepted, but building them requires a particular skill set. And which underlying technologies should be used? CSS animations? jQuery? GSAP? CreateJS? Once again, answers vary wildly among ad networks and publishers. The goal of this article isn't to provide an in-depth review or comparison of the various tools. Each has its own strengths and weaknesses, but let's briefly touch on some of the major runtime animation technologies: CSS transitions and CSS animations - these are supported in all modern browsers, but not IE9 or earlier. They're cheap from a file size standpoint and they perform well. For simple animations like button rollovers, they're great. However, file size rises quickly and things get cumbersome when you attempt even moderately complex animations. Simply put, they will take longer to build, they won't work in some older browsers, there are bugs (particularly when animating SVG elements), and certain tasks are outright impossible. Additional reading: https://css-tricks.com/myth-busting-css-animations-vs-javascript/ and http://greensock.com/transitions/ and https://css-tricks.com/svg-animation-on-css-transforms/ jQuery - it was never intended to be a robust animation tool, so jQuery suffers from poor performance and workflow issues. Most ad networks strongly advise against using it. GSAP is up to 20x faster. Additional reading: http://greensock.com/jquery/ CreateJS - Adobe Flash can optionally export to this canvas-based library. You can't just publish existing Flash banners to CreateJS (you must do some conversion work and leverage JavaScript instead of ActionScript) but for designers who are already used to the Flash interface, this can be a boon. One down side to canvas-based libraries is that you lose accessibility (the browser sees it as essentially a blob of pixels), but that's probably not a top priority for banners. File size can also become a concern (possibly mitigated by CDN standardization). You can use GSAP to animate CreateJS content. Additional reading: http://createjs.com Zepto - like a lightweight version of jQuery that uses CSS transitions under the hood for animations. Zepto is better than jQuery for banners, but it suffers from similar workflow issues as well as the inconsistencies/bugs inherent in CSS transitions/animations (like with SVG transforms). Active development seems to have stalled. Additional reading: http://zeptojs.com Web Animations - a new spec being worked on that has a lot of promise, but it just isn't a realistic contender at this point because it is in flux and several browser vendors remain noncommittal about ever supporting it. The polyfill has performance problems. Additional reading: http://w3c.github.io/web-animations GSAP - Widely recognized as the performance leader, GSAP solves all kinds of real-world animation problems from browser inconsistencies to workflow headaches (far too many to go into here). The Flash banner ad community is full of designers and developers who use GSAP daily, making it much easier to transition to HTML5; no new syntax to learn. Ongoing development and support have a solid track record for over 7 years. Additional reading: http://greensock.com/why-gsap/ Recommendations Based on our experience and the results from our survey, we suggest the following: Standardize a few JavaScript libraries Ideally, the IAB would equip the community with a short list of recommended libraries that get CDN-ified and exempted from file size calculations. Historically, the IAB has been extremely reluctant to officially endorse any third party tools. That's understandable - it could be seen as playing favorites or unfairly excluding someone's favorite library. However, without specific recommendations, the HTML5 landscape is so fractured and complex that it will result in a free-for-all (which is basically what it is now). The IAB can set the tone and move the focus away from aggregate total file sizes and into the modern era that leverages shared resources and browser caching to deliver excellent performance. It is imperative that this list of "recommended" libraries be very short, otherwise the caching impact will be diluted. The IAB can run their own independent tests and look at performance, features, compatibility, support, workflow benefits, and overall industry demand to determine which libraries get recommended. Of course we feel strongly that GSAP belongs on that list because: It is the top performer. It has widespread industry acceptance, both in Flash and HTML5. It's recommended by Google, used by the biggest brands in the world, etc. It is framework-agnostic, super flexible and robust, able to animate anything. It is professionally supported, yet free to use in banner ads. Modernize file size specs Given the 5.6x growth factor of bandwidth and page size since 2008, it seems entirely reasonable to adjust the old 40kb limit to 200kb (5x) for the modern HTML5 era. This is entirely consistent with some in-depth testing that has been done recently aimed at identifying the file size threshold at which real-world users perceive a dip in performance. The results showed that the threshold was upwards of 250kb. Combined file size isn't the only issue that contributes to slow load times; the number of server requests can have a significant impact. A single 300kb file can often load faster than 200kb split among 20 files. HTML5 banners can't realistically mash everything into one file, though. Doing so would kill the benefits of caching and resource sharing. So a reasonable compromise seems to be a 10-file maximum. Sprite sheets can be used to combine images. Given all the factors, we'd recommend the following for standard (non-rich media) ads: 200kb combined total (gzipped) Maximum of 10 files. Any additional must be loaded "politely" (after the parent page finishes loading) Shared CDN resources like GSAP don't count toward these totals. Some have suggested slicing the 200kb standard limit into two parts - a 50kb initial load, and then the rest "politely" loads. However, we advise against this for standard (non-rich media) ads because it unnecessarily complicates the design and production process as well as QA and enforcement. Rich media ads will likely require more files and kb than the limits mentioned above, and those should be polite-loaded. By "rich media", we mean ads that contain video or expand or perform API calls (like feeding the viewer's zip code to a backend script), etc. Update documentation and guidelines It is surprisingly difficult to get answers to some of the most basic questions when preparing a banner ad campaign for even the biggest networks and publishers. What are the file size limits? Which libraries can be used? Do CDN resources count against the total file size? Is there a network-specific CDN link for common libraries? Online docs either have outdated information or none at all related to HTML5. Drop support for IE8 Legacy IE support is not just painful for developers, it's exceedingly expensive for advertisers. Certain effects are outright impossible, so creatives must learn about the IE8 pitfalls and adjust their designs. Developers are forced to rebuild entire portions, implement workarounds and perform extra testing, all to accommodate a tiny fraction of the web audience who probably don't represent the demographic that advertisers are targeting anyway. This was never an issue for Flash, but it's a HUGE issue for HTML5 because it relies on native browser technologies that are absent from older browsers like IE8. Our recommendation is to draw a line in the sand and drop support for IE8 for sure, and potentially even IE9. Consider SVG instead of iframes Displaying ads inside an iframe is nice for security, but it forces ads into a strict rectangular space (ruling out fancy overlays with transparency/mask effects that show the main web page behind) and there's a performance price too. SVG is widely supported and it has some excellent transparency/masking capabilities, plus it can serve as a single container for an entire ad (see Chris Gannon's blog post and video)! Further testing needs to be done to better understand the performance and security implications, but it certainly seems like a worthwhile contender. Create a gallery of sample banners and templates Rather than pouring over specs and instructions and then building something from scratch, most developers prefer to analyze banners that already conform to the standards and use one as a template for their own project. Each network has different API's and ways you must track clicks, etc., so it would be lovely if each one provided a gallery of demos at each standard size. Codepen.io is a great place to host a collection because it's so easy to see (and edit) the HTML, CSS, and JS as well as the result all in one place. Developers can simply click the "fork" button and start producing their own version of that banner immediately in the browser. Codepen even integrates nicely with crossbrowsertesting.com for easy QA. Adjust client expectations As the industry transitions from Flash to HTML5, clients must be made aware of the design, budget, and schedule implications. HTML5 banners take more time to produce and test, therefore they will be more expensive. Plus there are certain effects that were easy in Flash but are virtually impossible in HTML5, so creative expectations need to be adjusted as well. Common GreenSock Questions With the broader discussion out of the way, let's narrow our focus to GreenSock for a moment and address some of the most frequently asked questions: Which networks support GSAP? All networks that we're aware of allow GSAP, and most even exempt its file size from the ads and host it on their CDNs. Google DoubleClick recommends GSAP for complex animations. Here's a breakdown of how some of the major players stack up: Allows GSAP Excludes GSAP from file size calculation* Hosts GSAP on CDN Advertising.com/AOL YES YES YES Google DoubleClick YES YES YES Flashtalking YES YES YES Sizmek YES YES YES Flite YES YES YES Cofactor YES YES YES AdWords YES YES YES *Unless publisher objects which is uncommon TweenMax is too big! Where's TweenNano? Let's face it: TweenMax (the most robust tool in the GSAP suite) is overkill for many banners that are only doing simple fades and movement. Wouldn't it be smart for GreenSock to create a super-small animation engine that's targeted at banners and only has the basic features? In the Flash days, we did exactly that and called it "TweenNano". It weighed about 2kb. On the surface, it sounds like a great idea but there are several reasons we avoided TweenNano in the HTML5 toolset: Caching - this is the biggest factor; loading the JavaScript file is a one-time hit and then the browser caches it, mitigating the entire loading issue on every page thereafter. Realistically, TweenNano must include a subset of TweenLite and CSSPlugin features and weigh at least 8kb; how much longer would it take for the average user to load an extra 25kb for TweenMax? It's not even noticeable (less than one second). So it doesn't seem like a worthwhile tradeoff to rip out all those features just to gain a fraction of a second only the first time it loads, especially for banners where caching and resource sharing could be used so effectively. If networks toss TweenMax.min.js on their CDNs, it effectively becomes "free" (zero load time) very quickly, giving them instant access to all the timeline tools plus a bunch of advanced plugins. Thus it seems smarter to press the full-featured, super-fast TweenMax engine into service rather than a sliced-down TweenNano with limited effects. Performance - GSAP has been engineered with a huge priority on performance which sometimes comes with a file size tradeoff. We could accomplish the same tasks with less code in places, but runtime performance would suffer. We feel strongly that when it comes to animation, it's wiser to pay a small up-front kb tax (only a fraction of a second in most cases) in order to get maximum runtime performance. Animations must look smooth and conserve battery power. Think of it this way: would you rather buy a computer that boots up 2 seconds faster or one that's 30% faster all the time (after it boots)? Flexibility/Creativity - what if you want to animate a non-essential CSS property like boxShadow or slide along a curve or scrub through a timeline? Even if there's just one part of your banner that needs a more advanced feature, it presents a dilemma. Creativity is hampered. Again, the fraction of a second one-time cost difference for TweenMax seems well worth it for the added flexibility and peace of mind. API confusion - years ago, Adobe created a lightweight version of the Flash Player dubbed "Flash Lite" with similar aspirations (bake only the essentials into a lighter weight flavor), but it was a complete failure. One of the problems was that developers couldn't remember which features were available in the regular Flash Player versus Flash Lite. Likewise, TweenNano's feature disparity would create some confusion/frustration. What about creating a tool that lets users select only the features they need, and then it spits out a customized stripped-down version of TweenMax? Again, this sounds appealing, but it would likely lead to worse load times because instead of having one common TweenMax that gets shared and cached, every banner would have its own different (and partially redundant) flavor to load. Ultimately, we're committed to delivering the tools that are needed most, so if the broader industry decides not to leverage shared resources and publishers insist on sticking to all-inclusive aggregate file size totals, we're open to creating TweenNano. Luckily, it looks like there's excellent momentum behind TweenMax getting CDN-ified and exempted from file size limits. In our opinion, that's definitely the smartest approach. What's so special about GSAP? It's beyond the scope of this article to explain all the benefits of using GSAP; see http://greensock.com/why-gsap/ for a summary. If you're still wondering what the big deal is, we'd encourage you to find someone who is proficient with it and ask about their experience. Usually people who take the time to learn it have a "light bulb" moment pretty quickly and never want to go back to using other libraries or CSS. It's difficult to explain to the uninitiated - lists of features don't really do it justice. It's not merely about performance (although that's a biggie) - it's about feeling empowered to animate almost anything you can imagine with minimal code. Do I need a commercial license to use GSAP in banner ads? GreenSock's standard "no charge" license covers usage in banner ads even if you get paid a one-time fee to produce the banners. We fully encourage the use of GSAP in banner ads and beyond. You may want to check out Club GreenSock for some bonus plugins that allow you to easily achieve advanced effects. Is anyone building a GUI for GSAP? A visual tool for building GSAP-based animations is a popular request, and we have been approached by several large and small companies about the possibilities, but there's nothing rock solid to report yet. We hope that companies like Adobe and Google will offer export options from their tools that leverage GSAP as the runtime engine and produce well-formatted, concise code. There's a pretty neat tool called Animachine that's in alpha and can be installed as a Chrome extension. It shows promise, but isn’t entirely stable at this point. There are also several online GSAP-based banner builders: http://html5maker.com/, https://tweenui.com/, and http://www.loxiastudio.com. Where can I get GSAP training? You can have GreenSock come directly to your organization and sit with your team to get them up to speed quickly. We can even convert one of your Flash banners and then teach you how we did it which is an excellent way to learn banner-specific tricks. The Q&A sessions are invaluable. We have limited slots available, though, so contact us as soon as possible to get your event scheduled. There are plenty of other learning resources available: GreenSock's getting started video/article GreenSock's learning resources New GreenSock eBook (published by Noble Desktop) Lynda.com course ihatetomatoes.net course (intermediate/advanced) Noble Desktop class in NYC 02Geek course Egghead.io The GreenSock forums are a fantastic place to not only ask your question(s), but also poke around and see what others are saying. It's one of the best places to learn even if you never ask a question. There are plenty of demos on codepen.io as well. For inspiration, we'd suggest following these people: Chris Gannon Sarah Drasner Petr Tichy Sara Soueidan Diaco.ml Blake Bowen Ico Dimchev UPDATE: The IAB released a draft of its new HTML5 specs and is soliciting public feedback before finalizing the document. The outstanding news is that they agreed with our assessment regarding a 200kb limit for standard ads. The IAB is expected to release an update to its HTML5 Best Practices guide soon which will likely contain a short list of JavaScript libraries that are recommended for exemption from file size calculations. We're confident GSAP will be on that list. #network-support { border-spacing: 1px; border-collapse: separate; background-color: #ccc; width: 830px; line-height: 1.1em; } #network-support thead td { background-color: #333; color: white; } #network-support td { text-align: center; vertical-align: bottom; font-family: Asap, Arial, sans-serif; padding: 10px 14px; background-color: white; } #network-support .network { text-align: left; font-weight: bold; } #network-support .yes { background-image: url(/wp-content/themes/greensock/images/licencing-check.png); } #network-support .yes, #network-support .no { background-color: white; background-repeat: no-repeat; vertical-align: middle; background-position: center center; background-size: 35px 35px; color: transparent; } .disclaimer { font-size: 11px; color: #777; padding: 2px; }

When it comes to animation, SVG and GSAP go together like peanut butter and jelly. Chocolate and strawberries. Bacon and...anything. SVG offers the sweet taste of tiny file size plus excellent browser support and the ability to scale graphics infinitely without degradation. They're perfect for building a rich, responsive UI (which includes animation, of course). However, just because every major browser offers excellent support for displaying SVG graphics doesn't mean that animating them is easy or consistent. Each browser has its own quirks and implementations of the SVG spec, causing quite a few challenges for animators. For example, some browsers don't support CSS animations on SVG elements. Some don't recognize CSS transforms (rotation, scale, etc.), and implementation of transform-origin is a mess. Don't worry, GSAP smooths out the rough spots and harmonizes behavior across browsers for you. There are quite a few unique features that GSAP offers specifically for SVG animators. Below we cover some of the things that GSAP does for you and then we have a list of other things to watch out for. This page is intended to be a go-to resource for anyone animating SVG with GSAP. Outline Challenges that GSAP solves for you Scale, rotate, skew, and move using 2D transforms Set the transformOrigin (the point around which rotation and scaling occur) Set transformOrigin without unsightly jumps Transform SVG elements around any point in the SVG canvas Animate SVG attributes like cx, cy, radius, width, etc. Use percentage-based x/y transforms Drag SVG elements (with accurate bounds and hit-testing) Move anything (DOM, SVG) along a path including autorotation, offset, looping, and more Animate SVG strokes Morph SVG paths with differing numbers of points Tips to Avoid Common Gotchas Limitations of SVG Browser support Inspiration Awesome SVG Resources Get Started Quickly with GSAP Challenges that GSAP solves for you GSAP does the best that it can to normalize browser issues and provide useful tools to make animate SVG as easy as it can be. Here are some of the challenges that using GSAP to animate SVG solves for you: Scale, rotate, skew, and move using 2D transforms When using GSAP, 2D transforms on SVG content work exactly like they do on any other DOM element. gsap.to("#gear", {duration: 1, x: 100, y: 100, scale: 0.5, rotation: 180, skewX: 45}); Since IE and Opera don't honor CSS transforms at all, GSAP applies these values via the SVG transform attribute like: <g id="gear" transform="matrix(0.5, 0, 0, 0.5, 100, 0)">...</g> When it comes to animating or even setting 2D transforms in IE, CSS simply is not an option. #gear { /* won't work in IE */ transform: translateX(100px) scale(0.5); } Very few JavaScript libraries take this into account, but GSAP handles this for you behind the scenes so you can get amazing results in IE with no extra hassles. Set the transformOrigin (the point around which rotation and scaling occur) Another unique GSAP feature: use the same syntax you would with normal DOM elements and get the same behavior. For example, to rotate an SVG <rect> that is 100px tall by 100px wide around its center you can do any of the following: gsap.to("rect", {duration: 1, rotation: 360, transformOrigin: "50% 50%"}); //percents gsap.to("rect", {duration: 1, rotation: 360, transformOrigin: "center center"}); //keywords gsap.to("rect", {duration: 1, rotation: 360, transformOrigin: "50px 50px"}); //pixels The demo below shows complete parity between DOM and SVG when setting transformOrigin to various values. We encourage you to test it in all major browsers and devices. With MorphSVG, you can Morph <path> data even if the number (and type) of points is completely different between the start and end shapes! Most other SVG shape morphing tools require that the number of points matches. Morph a <polyline> or <polygon> to a different set of points Convert and replace non-path SVG elements (like <circle>, <rect>, <ellipse>, <polygon>, <polyline>, and <line>) into identical <path>s using MorphSVGPlugin.convertToPath(). Optionally define a "shapeIndex" that controls how the points get mapped. This affects what the in-between state looks like during animation. Simply feed in selector text or an element (instead of passing in raw path data) and the plugin will grab the data it needs from there, making workflow easier. MorphSVGPlugin is a bonus plugin for Club GreenSock members (Shockingly Green and Business Green). Tips to Avoid Common Gotchas There are some things that GSAP can't solve for you. But hopefully this part of the article can help prepare you to avoid them ahead of time! Here are some things to keep in mind when creating and animating SVGs. Vector editor/SVG creation tips: When creating an SVG in Illustrator or Inkscape, create a rectangle the same size as your artboard for when you copy elements out of your vector editor and paste them into a code editor (how-to here). How to quickly reverse the direction of a path in Illustrator (Note: If the Path Direction buttons are not visible in the attributes panel, click the upper right menu of that panel and choose 'Show All'): Open path: Select the pen tool and click on the first point of your path and it will reverse the points. Closed path: Right click the path and make it a compound path, choose menu-window-attributes and then use the Reverse Path Direction buttons. If you're morphing between elements it might be useful to add extra points yourself to simpler shapes where necessary so that MorphSVG doesn't have to guess at where to add points. You can think of masks as clip-paths that allow for alpha as well. When using masks, it's often important to specify which units to use. Use a tool like SVGOMG (or this simpler tool) to minify your SVGs before using them in your projects. Code/animation-related tips: Always set transforms of elements with GSAP (not just CSS). There are quite a few browser bugs related to getting transform values of elements which GSAP can't fix or work around so you should always set the transform of elements with GSAP if you're going to animate that element with GSAP. Always use relative values when animating an SVG element. Using something like y: "+=100" allows you to change the SVG points while keeping the same animation effect as hard coding those values. You can fix some rendering issues (especially in Chrome) by adding a very slight rotation to your tween(s) like rotation: 0.01. If you're having performance issues with your issue, usually the issue is that you have too many elements or are using filters/masks too much. For more information, see this post focused on performance with SVGs. You might like injecting SVGs into your HTML instead of keeping it there directly. You can do this by using a tool like Gulp. You can easily convert between coordinate systems by using MotionPathPlugin's helper functions like .convertCoordinates(). Technique tips/resources: You can animate the viewBox attribute (demo)! You can animate (draw) a dashed line by following the technique outlined in this post. You can animate (draw) lines with varied widths by following the technique outlined in this post. You can animate (draw) handwriting effects by following the technique outlined in this post. You can create dynamic SVG elements! You can animate (draw) a "3D" SVG path. You can fake nested SVG elements (which will be available in SVG 2) by positioning the inner SVG with GSAP and scaling it (demo). You can fake 3D transforms (which will be available in SVG 2) in some cases by either Faking the transform that you need. For example sometimes rotationYs can be replaced by a scaleX instead. Applying the transform to a container instead. If you can limit the elements within the SVG to just the ones you want to transform, this is a great approach. For example, applying a rotationY to the <svg> or <div> containing a <path> instead of applying it to the <path> itself. Limitations of SVG The current SVG spec does not account for 3D transforms. Browser support is varied. Best to test thoroughly and have fallbacks in place. Most browsers don't GPU-accelerate SVG elements. GSAP can't change that. Browser support All SVG features in this article will work in IE9+ and all other major desktop and mobile browsers unless otherwise noted. If you find any cross-browser inconsistencies please don't hesitate to let us know in our support forums. Inspiration The Chris Gannon GSAP Animation collection is great for seeing more SVG animations made with GSAP. Be sure to also check out Chris Gannon's full portfolio on CodePen and follow him on Twitter for a steady influx of inspiration. Awesome SVG Resources SVG Tutorials - MotionTricks The SVG Animation Masterclass - Cassie Evans Understanding SVG Coordinate Systems and Transformations - Sara Soueidan Improving SVG Runtime Performance - Taylor Hunt SVG tips - Louis Hoebregts A Compendium of SVG Information - Chris Coyier Making SVGs Responsive with CSS - Sara Soueidan viewBox newsletter (SVG focus) - Cassie Evans and Louis Hoebregts Get Started Quickly with GSAP Below are a few resources that will get you up and running in no time: Getting Started Guide with Video Sequence Animations like a Pro (video) GSAP Documentation

Note: This page was created for GSAP version 2. We have since released GSAP 3 with many improvements. While it is backward compatible with most GSAP 2 features, some parts may need to be updated to work properly. Please see the GSAP 3 release notes for details. We're constantly improving GSAP to solve the problems you face as a developer/designer. In the recent release of GSAP 1.16.0 and 1.16.1, Draggable got some big upgrades and SVG support has never been better across the whole platform. Here's a summary of what's most exciting in 1.16.x: Draggable gets "autoScroll" What happens if you're dragging an element inside a scrollable container (or page) and you reach the edge? Wouldn't it be nice if it automatically scrolled in that direction for you? Wouldn't it be even cooler if it applied variable-speed scrolling based on how close your mouse/touch is to the edge, and it handle MULTIPLE containers? Wish granted. Video tour Interactive demo See the Pen Draggable autoScroll by GreenSock (@GreenSock) on CodePen. Draggable's new getDirection() method Sometimes it's useful to know which direction an element is dragged (left | right | up | down | left-up | left-down | right-up | right-down), or maybe you'd like to know which direction it is compared to another element. That's precisely what getDirection() is for. Video tour Interactive demo See the Pen Draggable getDirection() by GreenSock (@GreenSock) on CodePen. Easier SVG animation with svgOrigin For SVG elements, CSSPlugin recognizes a new svgOrigin special property that works exactly like transformOrigin but it uses the SVG's global coordinate space instead of the element's local coordinate space. This can be very useful if, for example, you want to make a bunch of SVG elements rotate around a common point. So you can do TweenLite.to(svgElement, 1, {rotation:270, svgOrigin:"250 100"}) if you'd like to rotate svgElement as though its origin is at x:250, y:100 in the SVG canvas's global coordinates. It also records the value in a data-svg-origin attribute so that it can be parsed back in. So for SVG elements, you can choose whichever one fits your project better: transformOrigin or svgOrigin. Sara Soueidan used this feature in her excellent Circulus tool demo. Interactive demo See the Pen GSAP svgOrigin by GreenSock (@GreenSock) on CodePen. For more information about how GSAP has solved cross-browser SVG challenges, see https://css-tricks.com/svg-animation-on-css-transforms/ and for performance data, see https://css-tricks.com/weighing-svg-animation-techniques-benchmarks/. More Draggable improvements Draggable exposes a lockedAxis property so that you can find out whether it's "x" or "y" (assuming you set lockAxis:true in the config object). New onLockAxis callback that fires whenever the axis gets locked. Several performance optimizations were made to Draggable, particularly for transforms and scrolling. Draggable allows you to native touch-scroll in the opposite direction as Draggables that are limited to one axis. For example, a Draggable of type:"x" or "left" permit native touch-scrolling in the vertical direction, and type:"y" or "top" permit native horizontal touch-scrolling. SVG support is better than ever. It plots the rotational origin accurately, for example. Touch support has been improved as well. Bug fixes See the github changelogs for 1.16.0 and 1.16.1 for a complete list. Conclusion If you're already using GSAP and/or Draggable, we definitely recommend grabbing the latest version. If you haven't tried GSAP yet, what are you waiting for? Head over to the Getting Started article/video now and you'll be having fun in no time. Helpful links Getting Started with GSAP Draggable demo and main page Draggable docs GSAP docs Got questions? Visit the forums

Note: This page was created for GSAP version 2. We have since released GSAP 3 with many improvements. While it is backward compatible with most GSAP 2 features, some parts may need to be updated to work properly. Please see the GSAP 3 release notes for details. The following is a guest post by Chris Gannon. Chris is the leading authority on using GSAP with Edge Animate. A veteran of the Flash world, Chris has been applying his animation and design skills to many cutting-edge HTML5 projects. We asked Chris to explain to our audience some of the techniques that he uses in his client work and top-selling components on CodeCanyon.net. The concepts he describes have many practical applications and can serve to radically transform how you approach complex projects. Be sure to explore the demos and study the source code. This is not intended to be a step-by-step tutorial. .wide .content p { font-size:20px; } I love 3D stuff and I'm always trying out interesting ways to add depth to my projects. In this article I'll talk about how the CubeDial below was made, the concepts surrounding its underlying mechanism and how some of the solutions I employ overcome some common issues. Ok, so let's get going. Explore the CubeDial demo In the demo below, spin the dial. Notice that spinning the dial spins the cube. You can also swipe the cube and the dial will spin. Both the cube and the dial spin using momentum-based physics. If you are really clever, you may notice that the cube isn't really a cube, as it has 6 front-facing sides. See the Pen Gannon - Cube / Dial by GreenSock (@GreenSock) on CodePen. What's it using under the hood? The core functionality is handled by the GreenSock Animation Platform (GSAP). I always load TweenMax because it includes all the things I need in one script load: TweenLite, CSSPlugin, EasePack, timeline sequencing tools, etc. I use TweenMax all over the place not only to immediately set CSS properties (using TweenMax.set() but also to delay the setting of them, to tween them, and to trigger events not only when they start or stop but crucially whilst they're animating too. Next up is Draggable - a very useful and flexible utility that I use in practically all of my projects now as most UIs need something dragged or moved. Finally we add in ThrowPropsPlugin (and couple it up to Draggable) for that flick/throw/physics/inertia that we have all become so used to on our mobile devices. So the three main GreenSock tools I will be using are: Draggable, TweenMax and ThrowPropsPlugin. The Cube's Structure A lot of you reading this will be visually led developers so below is a diagram of what's going on with the cube (ok it's a hexahedron I think as it has 6 sides). Each face of the 3D object is a <div> with a background image. Each <div> has its Z transformOrigin point set a fair bit away from the actual face (behind it) so that when its rotationY is animated it pivots left to right in perspective. This diagram illustrates the 6 faces - their transformOrigin X and Y are simply set to the middle of the faces (50% 50%) but the crucial part is the transformOrigin Z position which is -200px. In the actual code I dynamically work out what that distance should be based on the number of faces but to keep the diagram simple, I use -200px. The dotted center is that value (-200px) and once that's set each face will appear to swing around a point 200px behind itself when you tween its rotationY. By spinning each face around the same point, we achieve the illusion of the entire cube spinning around its center. To programmatically figure out the rotational offset of each face I use this equation: rotationY: (360/numFaces) * i; What wizardry is used to make a 6-sided object look like a cube? There's a simple answer to this and to demonstrate what's going on I have coded it so that all the faces become slightly transparent when you drag the cube. Try dragging and then holding it halfway through a drag - you'll see the other faces are distorted behind (see sceenshot on left). That's because the transformPerspective on each face is set fairly low (meaning exaggerated) in order to 'bend' the other faces behind. I've also added a slider to help illustrate this in the demo at the top of the page. As you drag the slider, the faces' transformPerspective is set higher and higher to the point where if the slider is fully to the right the perspective is so flat that the cube looks more like an infinite slide show. Try dragging it halfway then spinning the dial or the cube. Creating the dial In simple terms, the dial is just a png with some divs with some numbers in them. I do a little loop based on the number of sides in the cube to generate those divs and position them over the dial image. To make the dial "spin-able" literally takes one line of code using GSAP's Draggable. myDialDraggable = Draggable.create(dial, { type:'rotation', throwProps:true // for momentum-based animation }) That's really all you need to spin something. Amazing. However, the dial I use for this project is a little more advanced. I've isolated some of the dial's code in the demo below. Take note of how the numbers stay vertically oriented as the dial spins. Spin the dial See the Pen Gannon - Dial Only by GreenSock (@GreenSock) on CodePen. Using this method keeps everything in sync and it allows for multiple UI inputs - the null object is always controlled by user interaction and its X position is used to determine the rotation value of the dial (if the cube is dragged) and rotationY value(s) of the faces (if the dial is dragged). You can also use it to work out which face is at the front and because Draggable has the brilliant snap function you can ensure that when you release your drag/throw on either the 3D element or the dial it will always animate the null (and consequently all dependent objects) to a position where a face is flat on. Once it's come to rest you can also fire an onComplete event and have something happen - you might want the active/front face to load an iframe or animate its content. Or maybe you'd like a sound to play or you might want to perform a calculation based on the X position of null. Examples of using onComplete to trigger an animation when the spin is complete can be seen in demos for EdgeRotater and EdgeDial. Interacting with the 3D cube Unlike the simplified 2D demo above, grabbing and throwing the cube is a little more involved. The secret here is that you aren't directly touching the cube at all. In fact it would be literally impossible to effectively drag the cube by a face as the face would eventually disappear in to the distance of 3D space and overlap with other faces. It would be extremely difficult to assess which face receives the touch / mouse input for dragging. To solve this issue a Draggable instance is created that has the null object as its target and uses the <div> that contains the faces of the cube as its trigger. In simple terms this means that any time you click and drag on the div containing the cube it controls the x position of the null object, which in turn sets the rotation of each face of the cube and the rotation of the dial. Its sort of like interacting with a touch screen. There is a piece of glass between you and the UI elements you tap. Where you tap on the screen dictates which UI elements respond to your input. In the CubeDial, the div that contains the cube is like the glass screen of your phone. As you move your finger over the container, the app tracks your motion and applies the new values to the null object. Wrap up Ok that's enough of the complexities - it's hopefully not that complicated when you play around with it and adjust some values and see how things react. And if you're not already familiar with this kind of mechanism, once you've got your head around it you'll probably find you use it everywhere as it can be applied in pretty much all of your interactive projects. So that's all for now - I hope you found some (if not all) of this article interesting and/or informative. Admittedly it introduces the concept of null objects using a fairly complex example but it really doesn't have to be complex (or 3D). The 2D null object demo above might be a great place to start if all of this is pretty new to you as it uses a null object at its most basic level. Dive into the entire source code of the CubeDial Demo. My first draft of this article was peppered with gushing compliments regarding GSAP and I was told to tone it down a bit and maybe leave them until the end. So here it is (it's toned down a bit because I'm quite an excitable person!). GSAP rocks my world and the world of all my clients. If you aren't using it yet you are potentially missing out on one of the best (if not the best) animation platforms for JavaScript/CSS3. Its flexibility, ease of use and performance is light years ahead of anything else and if you're not using it and are curious then I heartily recommend you dive in and see for yourself. Jack has created amazing tools for designers and developers like us and Carl does an extraordinary job of explaining how they work in a simple, relevant and, most importantly, usable way. Happy tweening!

Note: This page was created for GSAP version 2. We have since released GSAP 3 with many improvements. While it is backward compatible with most GSAP 2 features, some parts may need to be updated to work properly. Please see the GSAP 3 release notes for details. There are some interesting (and surprising) performance implications of using CSS animations that aren't widely known. I stumbled across a few of them while running tests for a customer in the advertising industry who is pushing to have GSAP adopted as the standard, so I recorded a screencast explaining what I found. I figured it was worth sharing: Summary Timeline recordings in Chrome Dev Tools don't show the overhead involved with CSS animation of transforms, so people often misinterpret the [lack of] data. Recordings look "clean" with CSS and "dirty" with JS which leads to faulty conclusions about performance. CSS animations of transforms used twice as much CPU compared to JS according to Chrome's task manager. CSS animations caused the main thread to bog down more than using JavaScript animations. User interaction is typically handled on the main thread, making things feel sluggish to the user. It is especially costly if you animate transforms along with almost any other property at the same time. Webkit browsers have synchronization problems. JavaScript was faster than CSS animations on every device that I ran this test on – the only exception was animating transforms in Webkit browsers (and then there's that heavy cost on the main thread and sync problems). In order to independently control the timing/easing of transform components (rotation, scale, skew, position) in CSS, you must create a DOM node for each which negatively impacts performance. With JavaScript, no such workarounds are necessary. (see note below) I love Dev Tools - I'm not knocking it at all. These things are just tough to measure. Do your own tests! Don't put too much faith in Dev Tools or my tests. Use your eyes because ultimately perception is what matters to end users. Smooth movement and responsive UI are both important. Links Raw Codepen test Google's Paul Lewis addresses CSS vs. JS Animations A great article about hardware accelerated CSS by Ariya Hidayat Why GSAP? - a practical developer's guide UPDATE: After recording the video, I did some more tests that showed that one of the biggest contributors to the slowdowns in the pure CSS version was the fact that multiple elements had to be nested in order to accomplish the independent transform component controls. In other words, staggering the start/end times (or easing) of rotation, scale, and position is practically impossible in pure CSS unless you nest things like that, but there's a relatively significant performance tradeoff. When nesting could be avoided, pure CSS animation of only transforms did appear smoother on webkit browsers under heavy pressure and it was basically indistinguishable from optimized JS animations under all other levels of pressure.