js选下拉框 提交 （触发事件）

静态页面：

<meta http-equiv="content-type" content="text/html;charset=utf-8"><form name="form1" id="form1" method="post" action="server.php"><select name="rootid" id="rootid" onChange="changelocation()"> <option value="" selected>- 请选择 -</option> <option value="HK Island East">HK Island East</option> <option value="2">Yuen Long</option> <option value="3">Central and Western</option> <option value="4">Kwun Tong</option> <option value="5">HK Island South</option> <option value="6">Yau Tsim Mong</option> <option value="7">Tsuen Wan</option> <option value="8">Sham Shui Po</option> <option value="9">Wan Chai</option> <option value="10">Kowloon City</option> <option value="11">Tai Po</option> <option value="12">NT North</option> <option value="13">Remote Island</option> <option value="14">Sai Kung</option> <option value="15">Shatin</option> <option value="16">Sham Shui Po</option> <option value="17">Tseung Kwan O</option> <option value="18">Kwai Tsing</option> <option value="19">Tuen Mun</option> </select><script type="text/javascript">function changelocation(){    document.getElementById('form1').submit();}</script>

提交到程序：

<?php$conn=mysql_connect('localhost','root','');mysql_select_db('project');if (!$conn)  {  die('Could not connect: ' . mysql_error());  }mysql_select_db("project",$conn)or die(mysql_error()); mysql_query('set names UTF-8');var_dump($_POST['rootid']);$result = mysql_query("SELECT * FROM job where rootid='$rootid'"); while($row = mysql_fetch_array($result)){  echo"<tr>";echo"<th>" . $row['Job No'] . "</th>";echo"<th>" . $row['Project Type'] . "</th>";echo"<th>" . $row['District'] . "</th>";echo"<th>" . $row['Title'] . "</th>";echo"<th>" . $row['Google Map label'] . "</th>"; echo"</tr>";}    /*var_dump($_POST['rootid']);var_dump($_POST['areaid']);*/mysql_close($conn);?>