[web-animations] state and 2nd animate parameter

Hi web animators,Two questions:1) I have played around with the element.animate method in Chrome, with an image "i":var my_animation = i.animate([ { width: "10px" }, { width: "100px" } ], 1000);
When the animation is finished, is there a shortcut to set the "width" property of 
the element to the final value "100px"?  Right now it looks like it just resets to 
whatever the property was before the animate method was called.  (Currently 
I'm using the onfinish callback to achieve this.)
2) For element.animate(param1, param2), is there a list somewhere of all the 
possible names that can appear in the param2 object?  (name as in name:value 
pairs).
Thanks,Jonathan