解释几句代码javascript
<html><script>
function getDim(el){
var rd = {x:0,y:0}
do{
rd.x += el.offsetLeft
rd.y += el.offsetTop
el = el.offsetParent
} while(el)
return rd
}
</script>
<body>
<table><tr><td>
<span id=MySpan>aaaaaaa<img src="新建文件夹/icon/feiji.bmp" id=MyImage></span>
</td></tr></table>
<script>
mySpanDim = getDim(document.all.MySpan)
alert("x:" + mySpanDim.x + ", y:" + mySpanDim.y)
myImgDim = getDim(document.all.MyImage)
alert("x:" + myImgDim.x + ", y:" + myImgDim.y)
</script>
</body>
</html>
//上面函数的意思解释下呢`
补充：求救`现在就那个el返回的是什么值呢``
