<title>无标题文档</title>
<style>
#div1{ width:200px; height:200px; position:absolute; background:red;}
</style>
</head>
<script>
window.onload=function(){
var oDiv=document.getElementById('div1');
var disX=0;
var disY=0;
oDiv.onmousedown=function(ev){
var oEvent=ev || event;
disX=oEvent.clientX-oDiv.offsetLeft;
disY=oEvent.clientY-oDiv.offsetTop;
document.onmousemove=function(ev){
var oEvent=ev || event;
var l=oEvent.clientX-disX;
var t=oEvent.clientY-disY;
if(l<0){
l=0;
}
else if(l>document.documentElement.clientWidth-oDiv.offsetWidth)
{
l=document.documentElement.clientWidth-oDiv.offsetWidth;
}
if(t<0){
t=0;
}else if(t>document.documentElement.clientHeight-oDiv.offsetHeight)
{
t=document.documentElement.clientHeight-oDiv.offsetHeight;
}
oDiv.style.left=l+'px';
oDiv.style.top=t+'px';
}
document.onmouseup=function(){
document.onmousemove=null;
document.onmouseup=null;
}
}
}
</script>
<body>
<div id="div1"></div>
</body>
</html>
