<Script language="javascript">
<!--
function go(){
window.location=document.myweb.example.options[document.myweb.example.selectedIndex].value
}
//-->
</Script> 
<body>
<form name="myweb">请选择网址直接进入:
<select name="example" size=1 onChange="go()">
<option value="http://www.163.com">网易</option>
<option value="http://www.sohu.com">搜狐</option>
<option value="http://www.sina.com.cn">新浪</option>
<option value="http://www.baidu.com">百度</option>
<option value="http://www.google.com">Google</option>
</select>
</form>