<script src="jquery.min.js" type="text/javascript"></script>
 <script language="javascript" type="text/javascript">
 $(document).ready(function(){
 $('#mySelect').change(function(){
 alert($(this).children('option:selected').val());
 var p1=$(this).children('option:selected').val();//这就是selected的值
 var p2=$('#param2').val();//获取本页面其他标签的值
 window.location.href="xx.php?param1="+p1+"¶m2="+p2+"";//页面跳转并传参
 </script>
 <select id="mySelect">
 <option value="1">one</option>
 <option value="2" selected="selected">two</option>
 <option value="3">three</option>
 </select>
 <input type="text" value="ooo" name="param2" id="param2"/>

纯js

<script type="text/JavaScript">