I am in the midst of modifying a plugin in which I wish to get a value from a select list and auto-populate a textarea with values based on the selected value.

The php code come from a file named wpf-addusers.php but this file is not directly diplayed. The (absolute)url of the page that displays this information is http://localhost:8888/dev_wordpress/wp-admin/admin.php?page=mfgroups&mingleforum_action=usergroups&do=add_user_togroup.

My javascript (ajax) looks like this:


jQuery('#usergroup').change(function() {

      type: "GET",
      url: "wpf-addusers.php",
      data: { usergroup: jQuery(this).find(':selected').val() }
      }).done(function( results ) {
      console.log( results );



When I use "wpf-addusers.php" I get a 404 error like so: GET http://localhost:8888/dev_wordpress/wp-admin/wpf-addusers.php?usergroup=The+Freedom 404 (Not Found)

The+Freedom is the value I want to use in my php code:

$usergroups = $mingleforum->get_usergroups();
$team_title = $_GET[ 'usergroup'];
$team_id = $wpdb->get_var( "SELECT ID FROM $wpdb->posts WHERE post_title = '" . $team_title . "'" );
$players = get_users( array (
'meta_key' => 'team-meta',
'meta_value' => $team_id

echo "<div class='wrap'>
 <h2><img src='$image'> Add users</h2>";
echo "<form name='add_usertogroup_form' action='admin.php page=mfgroups&mingleforum_action=usergroups' method='post'>
<table class='widefat'>
      <th>User group</th>
      <th>User names </th>
  <tr class='alternate'>

    <td>"; echo "<select name='usergroup' id='usergroup'>
        <option selected='selected' value='add_user_null'>".__("Select User group", "mingleforum")."

        foreach($usergroups as $usergroup){
        echo "<option value='". $usergroup->id ."'>" . $usergroup->name . "</option>";

            echo "</select></td>

     <td>"; echo "<textarea name='togroupusers' rows='10' columns='60'>";
            if ( isset($_GET[ 'usergroup'])){
                foreach($players as $player) {
                    echo $player->display_name . ", ";
            echo "</textarea>";

    echo "<br/>
    <i>The above players will be added to the group.</i></td>
  <tr class='alternate'>
    <td colspan='2'><input class='button' name='add_user_togroup' type='submit' value='".__("Add users", "mingleforum")."' /></td>

Does anyone know how I can pass 'usergroup' to my php code?

By the way, My javascript is enqueued properly on the admin side. So I presume I don't a specific handler function for ajax? (That isn't the question just a sidenote)

1 Answer 1


You say that the page URL is http://localhost:8888/dev_wordpress/wp-admin/admin.php?page=mfgroups&mingleforum_action=usergroups&do=add_user_togroup but you are trying to load http://localhost:8888/tankards_wordpress/wp-admin/wpf-addusers.php?usergroup=The+Freedom. Those don't match is a number of ways, but I am not 100% sure what the relationship between the two is. Your question is not clear in that respect.

However, even if you got that .php file to load via direct access like that-- http://localhost:8888/tankards_wordpress/wp-admin/wpf-addusers.php?usergroup=The+Freedom--, it wouldn't work. If you load the file directly like that WordPress does not load, meaning that WordPress functions will not be defined, and that file depends on WordPress functions.

You should be using the AJAX API for this, as for nearly all AJAX used in a WordPress context-- cases needing extreme performance possibly excluded.

Write your PHP into a callback function like this:

add_action('wp_ajax_my_action', 'my_action_callback');

function my_action_callback() {
    // your PHP
    die(); // this is required to return a proper result

And pass my_action as part of your AJAX POST data, like this:

var data = {
    action: 'my_action',
    whatever: 1234

// since 2.8 ajaxurl is always defined in the admin header and points to admin-ajax.php
$.post(ajaxurl, data, function(response) {
    alert('Got this from the server: ' + response);

(Both example code blocks more or less cribbed from the Codex)

  • The urls don't match because I edited the error from a different install. I tried to tidy it up to match but I see what you mean. I basically wanted to show that the value was being passed in the url but not onto the page where I wanted it to appear. My code works if I type usergroup=The+Freedominto the url bar but I can't get it from the select menu. The AJAX API is a bit beyond me and I think I'm going to have to pick apart the plugin and find another way to get the value. Thanks for your answer.
    – mantis
    Jul 18, 2013 at 14:23
  • The AJAX API is dead simple, seriously. Take few minutes to get that working. You will never look back. It solves a number of tedious problems with AJAX, and other "run code from an URL" problems too actually.
    – s_ha_dum
    Jul 18, 2013 at 14:26
  • Alright, I'll knuckle down and have a look at it tonight. I'm sure I'll need it eventually and it would help me avoid hacking the plugin to bits. I'll let you know if I manage.
    – mantis
    Jul 18, 2013 at 16:18

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge that you have read and understand our privacy policy and code of conduct.

Not the answer you're looking for? Browse other questions tagged or ask your own question.