title: alert should close after 5 seconds
body: <p>I have simple javascript alert box i want it to close automatically after 5 second.
  if possible help please.</p>
  
  <pre><code>&lt;script type="text/javascript"&gt;
  function show_alert()
  {
  alert("Hello! I am an alert box!");
  }
  &lt;/script&gt;
  
  &lt;input type="button" onclick="show_alert()" value="Show alert box" /&gt;
  </code></pre>