Change attributes defined in defs on use element

Question

How can I achieve changing the style of an \"use element\", defined in defs, through scripting? I was trying to move in the w3c working draft interfaces, but I lost in that laby

Answer 1

To add to @Phrogz answer, It looks like even if i try to overwrite the styles defined inside the symbol tag its not getting overwritten in the use tag. A fiddle for that http://jsfiddle.net/rajkamal/xrdgf/