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Welcome! In this article we’re going to cover GSAP's core fundamentals and animate some HTML elements. If that’s not your end goal, don’t worry. Whatever you plan to animate, whichever framework you use - the techniques and principles covered here will serve you well. If you just want to jump in, here are some handy links. Full documentation GSAP cheatsheet CodePen starter template Installation guide. Still with us? Wonderful, let's get started! What is "GSAP"? The GreenSock Animation Platform (GSAP) is an industry-celebrated suite of tools used on over 11 million sites, including more than 50% of award‑winning ones! You can use GSAP to animate pretty much anything JavaScript can touch, in any framework. Whether you want to animate UI, SVG, Three.js or React components - GSAP has you covered. The core library contains everything you need to create blazing fast, cross-browser friendly animations. This is what we'll be stepping through in this article. In addition to the core, there are a variety of plugins. You don’t need to learn them in order to get started, but they can help with specific animation challenges like scroll based animation, draggable interactions, morphing, etc. See an overview of the available plugins. Creating an animation. Let's start by animating an HTML element with a class of "box". gsap.to(".box", { x: 200 }) A single animation like this is called a 'tween'. This tween is saying "hey GSAP, animate the element with a class of '.box' to an x of 200px (like transform: translateX(200px))".

If you find yourself writing multiple tweens to animate one target, it may be time to reach for keyframes. Keyframes are a great way to move a target through a series of steps while keeping your code concise. Take a repetitive timeline like the one below — It can be simplified down nicely to fit into one tween: // timeline let tl = gsap.timeline(); tl.to(".box", { x: 100 }) .to(".box", { y: 100 }) .to(".box", { x: 0 }) .to(".box", { y: 0 }); // Array-based keyframes gsap.to(".box", { keyframes: { x: [0, 100, 100, 0, 0], y: [0, 0, 100, 100, 0], ease: "power1.inOut" }, duration: 2 }); We like to think of keyframes as a sub-timeline nested inside a tween. There are a few different ways to write keyframes. If you're a visual learner, check out this video. Keyframe Options Object keyframes - v3.0 This keyframes syntax lets you pass in an Array of vars parameters to use for the given target(s). Think of them like a sequence of .to() tween vars. You can use a delay value to create gaps or overlaps. The default per-keyframe ease is linear which you can override in individual keyframes. You can also apply an ease to the entire keyframe sequence. gsap.to(".elem", { keyframes: [ {x: 100, duration: 1, ease: 'sine.out'}, // finetune with individual eases {y: 200, duration: 1, delay: 0.5}, // create a 0.5 second gap {rotation: 360, duration: 2, delay: -0.25} // overlap by 0.25 seconds ], ease: 'expo.inOut' // ease the entire keyframe block }); Percentage keyframes - v3.9 This familiar syntax makes porting animations over from CSS a breeze! Instead of using delays and duration in the keyframe object, you specify an overall duration on the tween itself, then define the position of each keyframe using percentages. To be consistent with CSS behaviour, the default per-keyframe ease is power1.inOut which generally looks quite nice but you can override this in individual keyframes or on all keyframes using easeEach. gsap.to(".elem", { keyframes: { "0%": { x: 100, y: 100}, "75%": { x: 0, y: 0, ease: 'sine.out'}, // finetune with individual eases "100%": { x: 50, y: 50 }, easeEach: 'expo.inOut' // ease between keyframes }, ease: 'none' // ease the entire keyframe block duration: 2, }) Simple Array-based keyframes - v3.9 Just define an Array of values and they'll get equally distributed over the time specified in the tween. The default per-keyframe ease is power1.inOut, but you can override this by using easeEach. The Arrays do not need to have the same number of elements. gsap.to(".elem", { keyframes: { x: [100, 0, 50], y: [100, 0, 50] easeEach: 'sine.inOut' // ease between keyframes ease: 'expo.out' // ease the entire keyframe block }, duration: 2, }) Easing keyframes Easing is integral to animation and keyframes give you a huge amount of flexibility. Percentage keyframes and Simple keyframes allow you to control the ease between each of the keyframes with easeEach. See the Pen Keyframe easing by GreenSock (@GreenSock) on CodePen. With Object keyframes and Percentage keyframes you can drill down and add different eases into individual keyframes. See the Pen Bounce Party with GSAP keyframes, by GreenSock (@GreenSock) on CodePen. You can even combine multiple easing properties, keyframes and normal tween values. 🤯 gsap.to(".box", { keyframes: { y: [0, 80, -10, 30, 0], ease: "none", // <- ease across the entire set of keyframes (defaults to the one defined in the tween, or "none" if one isn't defined there) easeEach: "power2.inOut" // <- ease between each keyframe (defaults to "power1.inOut") }, rotate: 180, ease: "elastic", // <- the "normal" part of the tween. In this case, it affects "rotate" because it's outside the keyframes duration: 5, stagger: 0.2 }); See the Pen keyframe easing by GreenSock (@GreenSock) on CodePen. Keyframe tips Both the Object keyframes and the Percentage keyframes behave similarly to tweens, so you can leverage callbacks like onStart and onComplete. gsap.to(".elem", { keyframes: [ {x: 100, duration: 1}, {y: 200, duration: 1, onComplete: () => { console.log('complete')}}, {rotation: 360, duration: 2, delay: -0.25, ease: 'sine.out'} ] }); gsap.to(".elem", { keyframes: { "0%": { x: 100, y: 100}, "75%": { x: 0, y: 0, ease: 'power3.inOut'}, "100%": { x: 50, y: 50, ease: 'none', onStart: () => { console.log('start')} } }, duration: 2, }) We hope this has helped you get your head around keyframes - if you have any questions pop over to our forums. Happy tweening!