JS获取DOM的高度包括Padding margin border

<div id="center"></div>

var dom=document.getElementById('center');var marginTop=getStyle(dom,'marginTop');alert(parseInt(marginTop));function getStyle(obj,attr){    if(obj.currentStyle){        return obj.currentStyle[attr];    }    else{        return document.defaultView.getComputedStyle(obj,null)[attr];    }