拖拽

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;
};

return false;
};
};