基于jquery的模态div层弹出效果

经过几多周折，终于搞出来了，效果图如下：

具体实现：
(1) 编写 jquery.divbox.js 的代码：

jQuery.fn.extend( 
{ 
OpenDiv: function() 
{ 
var sWidth, sHeight; 
sWidth = window.screen.availWidth; 
if (window.screen.availHeight > document.body.scrollHeight) 
{ 
sHeight = window.screen.availHeight; 
} else 
{ 
sHeight = document.body.scrollHeight + 20; 
} 
var maskObj = document.createElement("div"); 
maskObj.setAttribute('id', 'BigDiv'); 
maskObj.style.position = "absolute"; 
maskObj.style.top = "0"; 
maskObj.style.left = "0"; 
maskObj.style.background = "#111"; 
maskObj.style.filter = "Alpha(opacity=70);"; 
maskObj.style.opacity = "0.7"; 
maskObj.style.width = sWidth + "px"; 
maskObj.style.height = sHeight + "px"; 
maskObj.style.zIndex = "10000"; 
$("body").attr("scroll", "no"); 
document.body.appendChild(maskObj); 
$("#BigDiv").data("divbox_selectlist", $("select:visible")); 
$("select:visible").hide(); 
$("#BigDiv").attr("divbox_scrolltop", $.ScrollPosition().Top); 
$("#BigDiv").attr("divbox_scrollleft", $.ScrollPosition().Left); 
$("#BigDiv").attr("htmloverflow", $("html").css("overflow")); 
$("html").css("overflow", "hidden"); 
window.scrollTo($("#BigDiv").attr("divbox_scrollleft"), $("#BigDiv").attr("divbox_scrolltop")); 
var MyDiv_w = this.width(); 
var MyDiv_h = this.height(); 
MyDiv_w = parseInt(MyDiv_w); 
MyDiv_h = parseInt(MyDiv_h); 
var width = $.PageSize().Width; 
var height = $.PageSize().Height; 
var left = $.ScrollPosition().Left; 
var top = $.ScrollPosition().Top; 
var Div_topposition = top + (height / 2) - (MyDiv_h / 2); 
var Div_leftposition = left + (width / 2) - (MyDiv_w / 2); 
this.css("position", "absolute"); 
this.css("z-index", "10001"); 
this.css("background", "#fff"); 
this.css("left", Div_leftposition + "px"); 
this.css("top", Div_topposition + "px"); 
if ($.browser.mozilla) 
{ 
this.show(); 
return; 
} 
this.fadeIn("fast"); 
} 
, CloseDiv: function() 
{ 
if ($.browser.mozilla) 
{ 
this.hide(); 
} else 
{ 
this.fadeOut("fast"); 
} $("html").css("overflow", $("#BigDiv").attr("htmloverflow")); 
window.scrollTo($("#BigDiv").attr("divbox_scrollleft"), $("#BigDiv").attr("divbox_scrolltop")); 
$("#BigDiv").data("divbox_selectlist").show(); 
$("#BigDiv").remove(); 
} 
}); 
$.extend( 
{ 
PageSize:function () 
{ 
var width=0; 
var height=0; 
width=window.innerWidth!=null?window.innerWidth:document.documentElement&&document.documentElement.clientWidth?document.documentElement.clientWidth:document.body!=null?document.body.clientWidth:null; 
height=window.innerHeight!=null?window.innerHeight:document.documentElement&&document.documentElement.clientHeight?document.documentElement.clientHeight:document.body!=null?document.body.clientHeight:null; 
return {Width:width,Height:height}; 
} 
,ScrollPosition:function () 
{ 
var top=0,left=0; 
if($.browser.mozilla) 
{ 
top=window.pageYOffset; 
left=window.pageXOffset; 
} 
else if($.browser.msie) 
{ 
top=document.documentElement.scrollTop; 
left=document.documentElement.scrollLeft; 
} 
else if(document.body) 
{ 
top=document.body.scrollTop; 
left=document.body.scrollLeft; 
} 
return {Top:top,Left:left}; 
} 
}); 

(2) 网页中需引用两个js， jquery.divbox.js 和 jquery.js

(3) 测试页面代码：

复制代码代码如下:

<html> 
<head> 
<title>测试</title> 
<meta http-equiv="Content-Type" content="text/html; charset=gb2312"> 
<script type="text/javascript" src="js/jquery.js"></script> 
<script type="text/javascript" src="js/jquery.divbox.js"></script> 
<style> 
#divSCA 
{ 
position: absolute; 
width: 700px; 
height: 500px; 
font-size: 12px; 
background: #fff; 
border: 0px solid #000; 
z-index: 10001; 
display: none; 
} 
</style> 
<script type="text/javascript"> 
function openDiv() { 
$("#divSCA").OpenDiv(); 
} 
function closeDiv() { 
$("#divSCA").CloseDiv(); 
} 
</script> 
</head> 
<body> 
<div id="divSCA"> 
<font size="50">这是模态DIV,点击关闭</font> 
<input type="button" value="关闭" onclick="closeDiv()"> 
</div> 
<input type="button" value="弹出" onclick="openDiv()"/> 
测试能否覆盖 select 
<select> 
<option>测试1</option> 
<option>测试2</option> 
<option>测试3</option> 
</select> 
</body> 
</html> 