title: Error : Ajax is Undefined
body: <p>I am using the below code in a script tag to call one URL in the background.</p>
  
  <pre><code>var request = new Ajax.Request(logoffURL, {method : 'post'});
  </code></pre>
  
  <p>But I am getting script error <code>Ajax is undefined</code>.</p>
  
  <p>Do I need to include any external scripts?</p>