document.dafaultView为空

 #apDiv1 {
position:absolute;
left:145px;
top:120px;
width:194px;
height:180px;
z-index:1;
background:#00C;
}
</style>
<script language="javascript">
function gx()
{
var divObj=document.getElementById("apDiv1");
var divtop=document.defaultView.getComputedStyle(divObj,null).top;
var divleft=document.defaultView.getComputedStyle(divObj,null).left;
alert("上: "+divtop+"左 :"+divleft);
}
</script>
</head><body>
<div id="apDiv1" onclick="gx()">
测试
</div>