title: ScriptManager.RegisterStartupScript code not working - why?
body: <p>I have used code like this in the past to successfully pop up an alert message on my asp.net webpage. Now it is not working. I can't figure out why.</p>
  
  <pre><code>ScriptManager.RegisterStartupScript(this, typeof(Page), UniqueID, 
       "alert('This pops up')", true);
  </code></pre>
  
  <p>Any ideas?</p>