Update Query in Ajax

form.php:

 <?php
include('conn.php');
 if(isset($_GET['id2']))
{
        $id1=$_GET['id2'];
        session_start();
        $_SESSION['id1']=$id1;

        $select2 = mysql_query("SELECT *  from member where fid='$id1' ");
            $i=1;
        while($row1 = mysql_fetch_array($select2))
         {
        $fid=$row1['fid'];
        $memberslist=$row1['memberslist'];

?>

 <p style="text-align:center; font-size:18px;">Members:

<span id="txtHint2"><?php echo $memberslist;?></span></p>

<form action="" name="form1">
                 <tr ><td >

<select name="members" onchange="showCustomer2(this.value">

                 <option value="">Select</option>
                <option value="platinum" >Platinum</option>
                <option value="gold" >Gold</option>
                <option value="diamond" >Diamond</option>
                <option value="economical" >Economical</option>
                <option value="freelisting" >Freelisting</option>
  </select></td></tr><br>

script.php:

<script type="text/javascript">
function showCustomer2(str2)
{
//  alert("hi");
var xmlhttp;    
if (str2=="")
  {
  document.getElementById("txtHint2").innerHTML="";
  return;
  }
if (window.XMLHttpRequest)
  {// code for IE7+, Firefox, Chrome, Opera, Safari
  xmlhttp=new XMLHttpRequest();
  }
else
  {// code for IE6, IE5
  xmlhttp=new ActiveXObject("Microsoft.XMLHTTP");
  }
xmlhttp.onreadystatechange=function()
  {
  if (xmlhttp.readyState==4 && xmlhttp.status==200)
    {
    document.getElementById("txtHint2").innerHTML=xmlhttp.responseText;
    }
  }
xmlhttp.open("GET","member.php?q="+str2,true);
xmlhttp.send();
}
</script>

member.php:

<?php
include("conn.php");
session_start();
$id3=$_SESSION['id1'];
if(isset($_GET['q']))
{   

 $id1=$_GET['q'];

$update=mysql_query("update member set memberslist='$id1' where fid='$id3'"); 

      $select2 = mysql_query("SELECT *  from member where fid='$id3' ");
            $i=1;
        while($row1 = mysql_fetch_array($select2))
        {
      echo $row1['memberslist'];
        
    } }
?>