jquery模拟SELECT框

jquery模拟SELECT框，效果图如下：

<!DOCTYPE html>  
<html lang="en">  
<head>  
<title>jquery模拟SELECT框</title>  
<meta charset="utf-8">  
<style>  
body{padding:0;margin:0;font-size:12px;}  
ul,li{list-style:none;padding:0;margin:0;}  
#dropdown{width:186px; margin:100px auto; position:relative}    
.input_select{width:150px; height:24px; line-height:24px; padding-left:4px; padding-right:30px; border:1px solid #a9c9e2; background:#e8f5fe url(arrow.gif) no-repeat rightright 4px; color:#807a62; }    
#dropdown ul{width:184px; background:#e8f5fe; margin-top:2px; border:1px solid #a9c9e2; position:absolute; display:none}    
#dropdown ul li{height:24px; line-height:24px; text-indent:10px}    
#dropdown ul li a{display:block; height:24px; color:#807a62; text-decoration:none}    
#dropdown ul li a:hover{background:#c6dbfc; color:#369}    
#result{margin-top:10px;text-align:center}    
</style>  
<script type="text/javascript" src="http://jt.875.cn/js/jquery.js"></script>  
<script type="text/javascript">    
$(function(){    
    $(".input_select").click(function(){    
        var ul = $("#dropdown ul");    
        if(ul.css("display")=="none"){    
            ul.slideDown("fast");    
        }else{    
            ul.slideUp("fast");    
        }    
    });    
    $("#dropdown ul li a").click(function(){    
       var txt = $(this).text();  
        $(".input_select").val(txt);    
        var value = $(this).attr("rel");    
       $("#dropdown ul").hide();    
        $("#result").html("您选择了"+txt+"，值为："+value);    
    });    
        
});    
</script>    
</head>  
<body>  
  
<div id="dropdown">    
    <input class="input_select" type="text" value="请选择城市"/>  
    <ul>    
       <li><a href="#" rel="2">北京</a></li>    
       <li><a href="#" rel="3">上海</a></li>    
       <li><a href="#" rel="4">武汉</a></li>    
       <li><a href="#" rel="5">广州</a></li>    
    </ul>    
</div>    
<div id="result"></div>  
</body>  
</html>

补充：web前端 , JavaScript ,