本文实例讲述了JS实现新浪微博效果带遮罩层的弹出框代码。分享给大家供大家参考。具体如下：
这是一款新浪微博效果的弹出框，现成的JS代码，兼容IE6+，以及各主流浏览器。新浪微博弹出层并可拖拽，操作轻松舒适，符合用户的浏览习惯，将代码推荐给各位网友。
运行效果截图如下：
在线演示地址如下：
http://demo.phpstudy.net/js/2015/js-sina-zzxg-dlg-demo/
具体代码如下：
<!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>
body,html{height:2000px;}
body,div,h2{margin:0;padding:0;}
body{font:12px/1.5 Tahoma;}
center{padding-top:10px;}
button{cursor:pointer;}
#overlay{position:fixed;top:0;left:0;width:100%;height:100%;background:#000;opacity:0.5;filter:alpha(opacity=50);display:none;}
*html #overlay{position:absolute;}
#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 shit = !-[1, ];
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;
var iScrollT = document.documentElement.scrollTop || document.body.scrollTop;
var iScrollL = document.documentElement.scrollLeft || document.body.scrollLeft;
oBtn.onclick = function ()
{
oLay.style.display = "block";
oWin.style.display = "block";
shit && (oLay.style.height = document.body.offsetHeight + "px");
};
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 + iScrollL;
disY = event.clientY - oWin.offsetTop + iScrollT;
this.setCapture && this.setCapture();
return false
};
document.onmousemove = function (event)
{
if (!bDrag) return;
var event = event || window.event;
var iL = event.clientX - disX + iScrollL;
var iT = event.clientY - disY + iScrollT;
var maxL = document.body.clientWidth - oWin.offsetWidth;
var maxT = document.body.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>
<div id="overlay"></div>
<div id="win"><h2><span id="close">×</span></h2></div>
<center><button>弹出层</button></center>
</body>
</html>
希望本文所述对大家的JavaScript程序设计有所帮助。