php mysql wordpress自动完成无法正常工作

I have linked to the appropriate ajax library for autocomplete and jquery. Here is the script

 jQuery(document).ready(function($) {
 $("#tag").autocomplete("data.php", {
  selectFirst: true
   });
  });

and my data.php file

    $q = $_GET["q"];
   $my_data=mysql_real_escape_string($q);
  $sql="SELECT comname FROM wp_birds WHERE comname LIKE '%$my_data%' ORDER BY comname";
  $result = mysql_query($sql) or die(mysql_error());
  if($result)
  {
   while($row=mysql_fetch_array($result))
    {
   echo $row['comname']."
";
   }
 }

and my form

<label>Tag:</label>
<input name="tag" type="text" id="tag" size="20"/>

the data.php file is successfully loading the array of comnames however when i input i'm getting nothing...

jquery noconflict wrapper

jQuery(document).ready(function($) {
    $("#tag").autocomplete("data.php", {
      selectFirst: true
    });
});

reference: http://codex.wordpress.org/Function_Reference/wp_enqueue_script#jQuery_noConflict_Wrappers

Update:

You also need to retrieve your source using ajax

http://jqueryui.com/autocomplete/#remote

the jquery library included with wordPress loads in "no conflict" mode. This is done to prevent compatibility problems with other javascript libraries. In "no-confict" mode, the $ shortcut is not available and the longer jquery is used, Example :

jQuery(document).ready(function ($) {