I would like to animate the gradient mask's position from right to left on image, how do you accomplish this using Tweenmax that is compatible for most browsers specially on Chrome & Firefox?   **I was able to create a gradient mask in chrome using -webkit-mask-image but mask don't work on firefox**   HTML: <div id="gradient mask"> <div id="myimage"></div> </div> CSS: #myimage {     background-image: url(image.jpg);     width: 259px;     height: 194px;