js 弹出层并可以拖拽

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> 
<html xmlns="http://www.w3.org/1999/xhtml"> 
<head> 
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> 
<title>弹出层并可拖拽</title> 
<style> 
html,body{height:100%;overflow:hidden;} 
body,div,h2{margin:0;padding:0;} 
body{font:12px/1.5 Tahoma;} 
center{padding-top:10px;} 
button{cursor:pointer;} 
#overlay{position:absolute;top:0;left:0;width:100%;height:100%;background:#000;opacity:0.5;filter:alpha(opacity=50);display:none;} 
#win{position:absolute;top:50%;left:50%;width:400px;height:200px;background:#fff;border:4px solid #f90;margin:-102px 0 0 -202px;display:none;} 
h2{font-size:12px;height:18px;text-align:right;background:#FC0;border-bottom:3px solid #f90;padding:5px;cursor:move;} 
h2 span{color:#f90;cursor:pointer;background:#fff;border:1px solid #f90;padding:0 2px;} 
</style> 
<script> 
window.onload = function () 
{ 
var oWin = document.getElementById("win"); 
var oLay = document.getElementById("overlay"); 
var oBtn = document.getElementsByTagName("button")[0]; 
var oClose = document.getElementById("close"); 
var oH2 = oWin.getElementsByTagName("h2")[0]; 
var bDrag = false; 
var disX = disY = 0; 
oBtn.onclick = function () 
{ 
oLay.style.display = "block"; 
oWin.style.display = "block" 
}; 
oClose.onclick = function () 
{ 
oLay.style.display = "none"; 
oWin.style.display = "none"

}; 
oClose.onmousedown = function (event) 
{ 
(event || window.event).cancelBubble = true; 
}; 
oH2.onmousedown = function (event) 
{ 
var event = event || window.event; 
bDrag = true; 
disX = event.clientX - oWin.offsetLeft; 
disY = event.clientY - oWin.offsetTop; 
this.setCapture && this.setCapture(); 
return false 
}; 
document.onmousemove = function (event) 
{ 
if (!bDrag) return; 
var event = event || window.event; 
var iL = event.clientX - disX; 
var iT = event.clientY - disY; 
var maxL = document.documentElement.clientWidth - oWin.offsetWidth; 
var maxT = document.documentElement.clientHeight - oWin.offsetHeight; 
iL = iL < 0 ? 0 : iL; 
iL = iL > maxL ? maxL : iL; 
iT = iT < 0 ? 0 : iT; 
iT = iT > maxT ? maxT : iT;

oWin.style.marginTop = oWin.style.marginLeft = 0; 
oWin.style.left = iL + "px"; 
oWin.style.top = iT + "px"; 
return false 
}; 
document.onmouseup = window.onblur = oH2.onlosecapture = function () 
{ 
bDrag = false; 
oH2.releaseCapture && oH2.releaseCapture(); 
}; 
}; 
</script> 
</head> 
<body> 
 
<h2><span id="close">×</span></h2> 
<center><button>弹出层</button></center> 
</body> 
</html>

[Ctrl+A 全选注:如需引入外部Js需刷新才能执行]

js 弹出层 并可以拖拽

js 弹出层并可以拖拽