dynamically modify webkit animation with javascript

I would like to use webkit animation with @-webkit-keyframes but being able to dynamically modify the values on the rule, so that the animation is not static. All the samples I found use a static @-webkit-fr开发者_JS百科ames, is there a way to customize with Javascript?

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I had to create a new style rule in the loaded style sheets. Seems to work great in chrome 5.0.342.9 beta (at least)

var lastSheet = document.styleSheets[document.styleSheets.length - 1];
lastSheet.insertRule("@-webkit-keyframes " + newName + " { from { top: 0px; } to {top: " + newHeight + "px;} }", lastSheet.cssRules.length);

and then assign the animation name using element.style

element.style.webkitAnimationName = newName;

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I wish I could credit for this, but here's a link to someone who managed to modify an existing animation, as opposed to creating a new animation.

http://gitorious.org/webkit/webkit/blobs/438fd0b118bd9c2c82b6ab23956447be9c24f136/LayoutTests/animations/change-keyframes.html

I've ran this to verify that it does, indeed, work.

EDIT

So that link is dead and I don't trust Gitorious to maintain URLS anymore so here's a link to a JSFiddle I created to answer a similar question: http://jsfiddle.net/russelluresti/RHhBz/3/

This contains script to find an existing animation, update its values, and assign it to an element to make the animation occur. I have tested this in Chrome 18 and Safari 5.1