JavaScript弹出层后，让网页背景变暗，网上见的比较多了，常用于用户登录、网页消息、操作提示等方面，本代码例子可作为你的参考，大部分是用JS代码来实现的，可能对不熟悉JS的朋友来说，修改会成问题，不过会让前台页面很简洁，你可以将JS代码保存成一个JS文件，使用时引入，完整代码如下：
<html>
<head>
<title>JavaScript弹出层，背景变暗</title>
<script language="javascript">
var docEle = function() {
return document.getElementById(arguments[0]) || false;
}
function openNewDiv(_id) {
var m = "mask";
if (docEle(_id)) document.removeChild(docEle(_id));
if (docEle(m)) document.removeChild(docEle(m));
//激活Div层
var newDiv = document.createElement("div");
newDiv.id = _id;
newDiv.style.position = "absolute";
newDiv.style.zIndex = "9999";
newDiv.style.width = "300px";
newDiv.style.height = "200px";
newDiv.style.top = "100px";
newDiv.style.left = (parseInt(document.body.scrollWidth) - 300) / 2 + "px"; // 屏幕居中
newDiv.style.background = "EEEEEE";
newDiv.style.border = "1px solid #0066cc";
newDiv.style.padding = "5px";
newDiv.innerHTML = "这是一个Div弹出层";
document.body.appendChild(newDiv);
//mask层
var newMask = document.createElement("div");
newMask.id = m;
newMask.style.position = "absolute";
newMask.style.zIndex = "1";
newMask.style.width = document.body.scrollWidth + "px";
newMask.style.height = document.body.scrollHeight + "px";
newMask.style.top = "0px";
newMask.style.left = "0px";
newMask.style.background = "#000";
newMask.style.filter = "alpha(opacity=40)";
newMask.style.opacity = "0.40";
document.body.appendChild(newMask);
//关闭mask和新图层
var newA = document.createElement("a");
newA.href = "#";
newA.innerHTML = "关闭层";
newA.onclick = function() {
document.body.removeChild(docEle(_id));
document.body.removeChild(docEle(m));
return false;
}
newDiv.appendChild(newA);
}
</script>
</head>
<body>
<div id="newDiv"></div>
<a href="#" onclick="openNewDiv(newDiv);return false;">弹出层</a>
</body>
</html>本弹出层弹出后是可以关闭的，暂时没有写拖动功能。
