title: Trigger PHP function by clicking HTML link
body: <p>Is it possible to trigger a PHP function by just clicking a link? Or should I stick with the form submit method? If clicking the link will work, where should the link refer to?</p>
  
  <p>Here is a sample code:</p>
  
  <pre><code>&lt;?php
      session_start();
      function listMe($username){
          $username = mysql_real_escape_string($username);
          $query = mysql_query("INSERT INTO List (Usernames) VALUES ('$username')") or die(mysql_error());
      }
  ?&gt;
  
  &lt;html&gt;
      &lt;head&gt;
          &lt;title&gt;SAMPLE&lt;/title&gt;
      &lt;/head&gt;
      &lt;body&gt;
          &lt;a href="**__???___**"&gt;Add my username to the list&lt;/a&gt;
          &lt;?php 
              listMe($_SESSION['Username']); 
          ?&gt;
      &lt;/body&gt;
  &lt;/html&gt;
  </code></pre>
  
  <p>Maybe someone can point me in the right direction. Thanks!</p>