急救：我用鼠标拖动div时，怎么实现鼠标在此div的下面

Question

我现在是拖动div到一个span上面，当鼠标在span上面时，span的背景改变，这样能实现吗？？？？

Answer 1

不用设置鼠标透明度,按你在另一个帖子中所说
http://community.csdn.net/Expert/topic/4760/4760928.xml?temp=.3677942
只要设置对象的zIndex属性，使下面span的比上面div的大就可以了
或者设置css中的滤镜属性
filter:alpha(opacity=0)
用JS赋值的话可以用
obj.style.filter="alpha(opacity=0)"
语句实现

Answer 2

设置对象的zIndex属性行不同啊？？？？这是我写的帮忙看看，谢了
<script>
<!--
function setCookie(top,left)
{
    document.cookie="top="+top;
    document.cookie="left="+left;
}
function getCookie(name)
{
    var mycookie=document.cookie;
    var start=mycookie.indexOf(name+"=");
    if (start!=-1) 
    {
        start=mycookie.indexOf("=",start)+1;
        var end=mycookie.indexOf(";",start);
        if (end==-1)
        end=mycookie.length;
        var value=unescape(mycookie.substring(start,end));
        if (value!=null) 
        {
            var obj=document.getElementById("TheDiv");
            if (name=="top")
            obj.style.top=value;
            if (name="left")
            obj.style.left=value;
        }
    }
}
function moveobj(obj)
{
    var x=event.clientX;
    var y=event.clientY;
    obj.setCapture();
    function obj.onmousemove()
    {
        if(obj)
        {
            var nx=event.clientX;
            var ny=event.clientY;
            window.status="X="+nx+"Y="+ny;
            obj.style.posLeft+=nx-x;
            obj.style.posTop+=ny-y;
            x=nx;
            y=ny;
        }
    }
    function obj.onmouseup()
    {
        var stop=0;
        obj.releaseCapture();
        var nowtop=obj.style.top;
        var nowleft=obj.style.left;
        setCookie(nowtop,nowleft);
        obj=false;
    }
}
function setspan()
{
    span1.style.background="red";
}
//-->
</SCRIPT>
<div id="TheDiv" onmousedown="moveobj(this)" style=" float:left; position:absolute;width:200px;height:200px;background:#355ddd;border:1px #356999 solid;cursor:move; z-index:0;"></div>
<br/><br/><br/><br/><br/><br/><br/><br/><br/><br/><br/><br/>
<span id="span1" style="width:100px;height:100px;background:#355ddd; z-index:1;" onmouseover="setspan();">sjdfkdsjfkdfj</span>