对同一页面的Ajax调用无效

Question

I am getting records from database in WordPress then creating and adding value in select tag(HTML) dynamically.

<?php
global $wpdb;
$registeredUsers = $wpdb->get_results('SELECT * FROM wp_users where user_login != "Admin"',ARRAY_A);
$select='<select name="users" class="form-control" id="users">';
    $select.= '<option value="Select User"> Select User</option>';
         foreach($registeredUsers as $user)
         {
            $select.='<option value="'.$user['user_email'].'">'.$user['user_login'].'</option>';
         }
   $select.='</select>';
?>

I am using $select variable in Html and drop down is being displayed properly.

<form id="a" action="" method="post">
<div style="margin: 0 auto;width:500px;">
<?php echo $select ?>
</div>
</form>

I have written code to get selected drop down onchange event in jquery. It return success but I am not able to get selected value of dropdown.

<script type="text/javascript">
        $(document).ready(function(){
          $("select[name='users']").change(function () {
                jQuery.ajax({
                type: "POST",
                data:  $("form#a").serialize(),
        success: function(data){
            alert("SUCCESS");
                }
                });  
        });
        });
</script>

Below code return nothing

if(isset($_POST['users'])) {
echo $_POST['users'];
}

Answer 1

Set url option to your page in your ajax function:)

<script type="text/javascript">
        $(document).ready(function(){
          $("select[name='users']").change(function () {
                jQuery.ajax({
                type: "POST",
                url:"yourpage.php"
                data:  $("form#a").serialize(),
        success: function(data){
            alert("SUCCESS");
                }
                });  
        });
        });
</script>

replace yourpage.php