var $=function(id){return document.getElementById(id) };
方法一
/*
* @string id
* @string styleName 樣式名
*/
function getEyeJsStyle(id,styleName){
if($(id).currentStyle){//ie
return $(id).currentStyle[styleName];
}else{ //ff
var $arr=$(id).ownerDocument.defaultView.getComputedStyle($(id), null);
return $arr[styleName];
}
}

HTMLElement.prototype.__defineGetter__("currentStyle", function () {
return this.ownerDocument.defaultView.getComputedStyle(this, null);
});