本文实例分析了jQuery遮罩层效果。分享给大家供大家参考，具体如下：
先来看看示例代码：
<!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" xml:lang="zh" lang="zh" dir="ltr">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
</head>
<body>
<mce:script type="text/javascript" src="jquery-1.4.4.min.js" mce_src="jquery-1.4.4.min.js"></mce:script>
<title>Example | xHTML1.0</title>
<mce:style>
<!-- *{
font-family:Arial, Helvetica, sans-serif;
font-size:12px;
}
#full_box{
background-color:gray;
display:none;
z-index:3;
position:absolute;
left:0px;
top:0px;
filter:Alpha(Opacity=30);
/* IE */
-moz-opacity:0.4;
/* Moz + FF */
opacity: 0.4;
}
#dialog{
position:absolute;
width:200px;
height:200px;
background:#F00;
display:none;
z-index:5;
}
-->
</mce:style>
<style mce_bogus="1">
*{
font-family:Arial, Helvetica, sans-serif;
font-size:12px;
}
#full_box{
background-color:gray;
display:none;
z-index:3;
position:absolute;
left:0px;
top:0px;
filter:Alpha(Opacity=30);
/* IE */
-moz-opacity:0.4;
/* Moz + FF */
opacity: 0.4;
}
#dialog{
position:absolute;
width:200px;
height:200px;
background:#F00;
display:none;
z-index:5;
}
</style>
<mce:script type="text/javascript">
<!--
function showBox() {
var bH = $(window).height();
var bW = $(window).width();
$("#full_box").css({width:bW,height:bH,display:"block"});
var objWH = getObjWh('dialog');
var tbT = objWH.split("|")[0] + "px";
var tbL = objWH.split("|")[1] + "px";
$("#dialog").css({top:tbT,left:tbL,display:"block"});
$("#dialog_content").html("<div style="text-align:center" mce_style="text-align:center">正在加载，请稍后...</div>");
$(window).scroll(function (){ resetBox();});
$(window).resize(function (){ resetBox();});
}
function resetBox() {
var full_box = $("#full_box").css("display");
if (full_box == 'block') {
var bH = $(window).height();
var bW = $(window).width();
var objWH = getObjWh('dialog');
var tbT = objWH.split("|")[0] + "px";
var tbL = objWH.split("|")[1] + "px";
$("#dialog").css({top:tbT,left:tbL,display:"block"});
}
}
function getObjWh(obj) {
var st = $(window).scrollTop();
var sl = $(window).scrollLeft();
var ch = $(window).height();
var cw = $(window).width();
var objH = $("#"+obj).height();
var objW = $("#"+obj).width();
var objT = Number(st) + (Number(ch) - Number(objH))/2;
