title: Need to generate random number after time interval
body: <p>I'm using my own security form or you can say security challenge question.</p>
  
  <p>But the problem is that I have change that question daily manually.</p>
  
  <p>Is there any way to change it automatically after every 5 minutes?</p>
  
  <p>Here is code of this:</p>
  
  <pre><code>if (!$_POST['security_question'] || $_POST['security_question'] != '**PUT HERE YOUR QUESTION?**' ) {
   $errors[] = t('You must answer security question correctly!');
   }
  &lt;tr class="row1"&gt;
   &lt;td&gt;'.t('Security Question:').'&lt;/td&gt;
   &lt;td&gt;**PUT HERE YOUR QUESTION?**
  
   &lt;input type="text" name="security_question"/&gt;
   &lt;/td&gt;
   &lt;/tr&gt;
  </code></pre>
  
  <p>So I want to change the link "PUT HERE YOUR QUESTION?" in both case randomly after some time interval.</p>