js弹出层(jQuery插件形式附带reLoad功能)

之前做一个项目，感觉里面的弹出层做的挺好，但是代码结构有问题，这次用到了，重构了一下，改成jQuery的插件形式，并增加了reLoad的功能，感觉还不错，代码如下：

(function($){ 
$.module={ 
_showCoverLayer:function(){//显示遮盖层 
this.coverLayer=$("#TB_overlay"); 
var height=$(document).height()+"px"; 
var width=$(document).width()+"px"; 
if(this.coverLayer.length>0){ 
this.coverLayer.css({"visibility":"visible","height":height,"width":width}); 
}else{ 
this.coverLayer=$("<div id='TB_overlay' style='height:"+height+";width:"+width+"'></div>"); 
$("body").append(this.coverLayer); 
} 
}, 
_hideCoverLayer:function(){//隐藏遮盖层 
this.coverLayer.css("visibility","hidden"); 
}, 
_showAjaxLoad:function(imgUrl){ 
this.ajaxLayer=$("#TB_load"); 
if(this.ajaxLayer.length>0){ 
this.ajaxLayer.css({"visibility":"visible"}); 
$("#TB_loadContent").css({"display":"block"}); 
}else{ 
this.ajaxLayer=$("<div id='TB_load'><div id='TB_loadContent'><img src='"+imgUrl+"' /></div></div>"); 
$("body").append(this.ajaxLayer); 
} 
}, 
_hideAjaxLoad:function(){ 
this.ajaxLayer.css("visibility","hidden"); 
$("#TB_loadContent").css({"display":"none"}); 
}, 
showWin:function(opt){//url,title,width,height,fixTop,fixLeft,imgUrl,top 
this._showCoverLayer(); 
this.imgUrl=opt.imgUrl || "/image/ajax-loader.gif"; 
this._showAjaxLoad(this.imgUrl); 
this.win=$("#TB_window"); 
var that=this; 
if(this.win.length==0){ 
this.win=$("<div id='TB_window'></div>"); 
$("body").append(this.win); 
this.win.append("<div id='TB_closeAjaxWindow' style='cursor:move' onmousedown='drag(this.parentNode,event);'><span id='TB_close'>X</span><span id='TB_title'>"+opt.title+"</span></div><div id='TB_ajaxContent'></div>"); 
$("#TB_close").click(function(){ 
that.hideWin(); 
}); 
} this._init(opt); 
$("#TB_ajaxContent").load(opt.url, function() { 
that._hideAjaxLoad(); 
that.win.slideDown("normal"); 
}); 
}, 
hideWin:function(){ 
var that=this; 
this.win.fadeOut("fast",function(){ 
that._hideCoverLayer(); 
}); 
}, 
_init:function(opt){ 
$("#TB_title").html(opt.title); 
var top=opt.top || ( $(window).height() - opt.height ) /2+(opt.fixTop || 0);// +$(window).scrollTop() ; 
var left=( $(window).width() - opt.width ) / 2+(opt.fixLeft || 0);//+$(window).scrollLeft(); 
this.win.css({"height":opt.height+"px", 
"width":opt.width+"px", 
"top":top+"px", 
"left":left+"px" 
}); 
}, 
reLoad:function(opt){//加载新页面 
var that=this; 
this.win.fadeOut("fast",function(){ 
that._showAjaxLoad(that.imgUrl); 
that._init(opt); 
$("#TB_ajaxContent").load(opt.url, function() { 
that._hideAjaxLoad(); 
that.win.fadeIn("normal"); 
}); 
}); 
} 
} 
})(jQuery);

CSS代码如下：

body {background-color:#fff;} 
html, body {height:100%;} 
html body{font:12px Arial, Helvetica, sans-serif;color:#333333} 
html>body{font:12px Arial, Helvetica, sans-serif;color:#333333} 
#TB_overlay { 
position: absolute; 
top: 0; 
left: 0; 
z-index:100; 
width: 100%; 
height: 100%; 
background-color:#CCC; 
filter:alpha(opacity=60); 
-moz-opacity: 0.6; 
opacity: 0.6; 
} 
#TB_window { 
top: 0px; 
left: 0px; 
position: fixed; 
_position: absolute; 
background: #fff; 
z-index: 102; 
color:#000000; 
display:none; 
border:5px solid #666; 
} 
#TB_caption{ 
height:25px; 
padding:10px 30px 10px 25px; 
} 
#TB_closeWindow{ 
height:25px; 
padding:10px 25px 10px 0; 
float:right; 
} 
#TB_closeAjaxWindow{ 
padding:5px 10px 7px 0; 
margin-bottom:1px; 
text-align:right; 
background-color:#e8e8e8; 
} 
#TB_close{ 
cursor:pointer; 
} 
#TB_title{ 
float: left; 
font-weight: bold; 
margin-left: 10px; 
} 
#TB_ajaxContent{ 
padding:2px 15px 15px 15px; 
overflow:auto; 
} 
#TB_load{ 
text-align: center; 
position: fixed; 
top: 50%; 
left: 0px; 
width: 100%; 
overflow: visible; 
visibility: visible; 
display: block; 
z-index:101; 
} 
/*Download by http://sc.xueit.com*/ 
#TB_loadContent{ 
margin-left: -125px; 
position: absolute; 
top: -50px; 
left: 50%; 
width: 250px; 
height: 100px; 
visibility: visible; 
}

这样来使用：

$.module.showWin({url:"/deposit/clear/"+depositId+"?"+(+new Date), 
title:"清退关闭", 
width:550, 
height:350});

效果如下：
 
关闭的时候，这样调用：

$.module.hideWin();

这个弹出层有几个问题：
1、因为采用的是$.load()的方式，所以只能加载同源的url
2、在单页面的情况下，可以很好的定位，如果作为在iframe中弹出，则需要传入top值来辅助定位。这个问题是因为$(window).top()在单页面下和iframe下取的值不一样导致的，也不知该怎么解决。有了解的朋友说一下，不胜感激。