复制代码 代码如下:

<script language="javascript">

var MAX_INDEX=4;

function change(ddd)

{

if(ddd.style.zIndex<= MAX_INDEX)

{

ddd.style.zIndex = MAX_INDEX+1;

MAX_INDEX++;

}

}

</script>

<div id="layer1"></div>

<div id="layer2"></div>

<div id="layer3"></div>

<div id="layer4"></div>