After changing the animation-duration (or in this case, -webkit-animation-duration) property via JavaScript with setProperty(\"-webkit-animation-
Setting the style element directly using the [] to access either the vendor-prefixed or native css prop. will allow you to re-apply the animation duration property and change the rotational speed of the planet. No jquery needed. It's also worth mentioning that at the time of writing Firefox supports a non-prefixed version of the css property, while there is either mixed support or vendor-prefix support for other browsers. If considering using these animations, a given developer should seriously consider their potential user-base and probably not make this a core feature of web app. See more support info here:
http://caniuse.com/#feat=css-animation
Le code:
orbitFactor = 1e6
function updateSpeed(event) {
var orbitDiv = document.getElementById("Mercury-orbit");
orbitDiv.style["-webkit-animation-duration"] = event.target.value + "s";
}
function updateDiameter(event) {
var planetDiv = document.getElementById("Mercury");
planetDiv.style["width"] = event.target.value + "px";
planetDiv.style["height"] = event.target.value + "px";
}
document.getElementById("orbit-period").addEventListener("change", updateSpeed);
document.getElementById("planet-diameter").addEventListener("change", updateDiameter);