网页点击按钮弹出遮罩层，拖动和关闭效果
基于JavaScript的网页弹出层，鼠标按在弹出层的标题栏处，可以拖动该浮动层随意移动位置，不需要时也可以关闭，操作体验舒服，兼容性好，IE/火狐等众多浏览器下运行稳定、反应快速。代码表现方面，简洁务实，不玩虚的，拿去学习也相当不错。
<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<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;}
li{ list-style-type:none}
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>
<meta charset="utf-8">
</head>
<body>
<div id="overlay"></div>
<div id="win"><h2><span id="close">×</span></h2>
<li><a href='http://www.100sucai.com' target='_blank'>http://www.100sucai.com</a></li>
<li><a href="http://www.100sucai.com/web/jquerytexiao/CSS3heHtml5/" title="CSS3和Html5">CSS3和Html5</a></li>
<li><a href="http://www.100sucai.com/web/jquerytexiao/tubiaoyutuxing/" title="图表与图形">图表与图形</a></li>
</div>
<center><button>弹出层</button></center>
</body>
</html><br />
