jquery 弹出登录窗口实现代码

<div id="floatBoxBg">
<div id="floatBox" class="floatBox">
<div class="title"><h4>标题</h4><span>关闭</span></div>
<div class="content">内容</div>
</div>
</div>

#floatBoxBg {
display:none;
width:100%;
height:100%;
background:#000;
position:absolute;
top:0;
left:0;
}
.floatBox {
border:#0C7FDA 5px solid;
width:300px;
position:absolute;
top:50px;
left:40%;
z-index:1000;
}
.floatBox .title {
height:23px;
padding:7px 10px 0;
color:#fff;
background-attachment: scroll;
background-image:url(../images/dialog_bg.gif);
background-repeat: repeat-x;
background-position: 0px 0px;
}
.floatBox .title h4 {
float:left;
padding:0;
margin:0;
font-size:14px;
line-height:16px;
}
.floatBox .title span {
float:right;
cursor:pointer;
vertical-align:middle;
margin-bottom:2px;
}
.floatBox .content {
padding:20px 15px;
background:#fff;
}

// JavaScript Document

var dialogFirst=true;
function dialog(title,content,width,height,cssName){

if(dialogFirst==true){
var temp_float=new String;
temp_float="<div id=/"floatBoxBg/" style=/"height:"+$(document).height()+"px;filter:alpha(opacity=0);opacity:0;/"></div>";
temp_float+="<div id=/"floatBox/" class=/"floatBox/">";
temp_float+="<div class=/"title/"><h4></h4><span><img src=/"/upload/2009-12/20091224021446804.gif/" width=/"22/" height=/"23/" /></span></div>";
temp_float+="<div class=/"content/"></div>";
temp_float+="</div>";
$("body").append(temp_float);
dialogFirst=false;
}

$("#floatBox .title span").click(function(){
$("#floatBoxBg").animate({opacity:"0"},"normal",function(){$(this).hide();});
$("#floatBox").animate({top:($(document).scrollTop()-(height=="auto"?300:parseInt(height)))+"px"},"normal",function(){$(this).hide();});
});

$("#floatBox .title h4").html(title);
contentType=content.substring(0,content.indexOf(":"));
content=content.substring(content.indexOf(":")+1,content.length);
switch(contentType){
case "url":
var content_array=content.split("?");
$("#floatBox .content").ajaxStart(function(){
$(this).html("loading...");
});
$.ajax({
type:content_array[0],
url:content_array[1],
data:content_array[2],
error:function(){
$("#floatBox .content").html("error...");
},
success:function(html){
$("#floatBox .content").html(html);
}
});
break;
case "text":
$("#floatBox .content").html(content);
break;
case "id":
$("#floatBox .content").html($("#"+content+"").html());
break;
case "iframe":
$("#floatBox .content").html("<iframe src=/""+content+"/" width=/"100%/" height=/""+(parseInt(height)-70)+"px"+"/" scrolling=/"auto/" frameborder=/"0/" marginheight=/"0/" marginwidth=/"0/"></iframe>");
}

$("#floatBoxBg").show();
$("#floatBoxBg").animate({opacity:"0.5"},"normal");
$("#floatBox").attr("class","floatBox "+cssName);
$("#floatBox").css({display:"block",left:(($(document).width())/2-(parseInt(width)/2))+"px",top:($(document).scrollTop()-(height=="auto"?300:parseInt(height)))+"px",width:width,height:height});
$("#floatBox").animate({top:($(document).scrollTop()+50)+"px"},"normal");
}