下拉菜单

<!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">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>无标题文档</title>
<style type="text/css">
*{ margin:0px auto; padding:0px}
#xiala{ 200px; height:40px; border:1px solid #999;text-align:center; line-height:40px; vertical-align:middle;}
#xiala:hover{ cursor:pointer}
.list{ 200px; height:40px; text-align:center; line-height:40px; vertical-align:middle; border:1px solid #999; border-top-0px; display:none}
.list:hover{ cursor:pointer; background-color:#63C; color:white;}
</style>
</head>

<body>
<br />
<div style="500px; height:500px;">

	<div id="xiala" onclick="showa()"></div>
    <div class="list" onclick="xuan(this)">山东</div>
    <div class="list" onclick="xuan(this)">北京</div>
    <div class="list" onclick="xuan(this)">上海</div>
    <div class="list" onclick="xuan(this)">深圳</div>
    <div class="list" onclick="xuan(this)">广州</div>
    
</div>
<script type="text/javascript">
function showa()
{
	var list = document.getElementsByClassName("list");
	for(var i=0; i<list.length;i++)
	{
		list[i].style.display = "block";
	}
}

function xuan(a)
{
	var nr = a.innerHTML;
	document.getElementById("xiala").innerHTML=nr;
	
	var list = document.getElementsByClassName("list");
	for(var i=0; i<list.length;i++)
	{
		list[i].style.display = "none";
	}
}
</script>
</body>
</html>
　　效果如图：