How to display model popup at first time page load only
<p>I used the following code to display model popup for the first time page load,</p>

<pre><code>&lt;script type="text/javascript"&gt;
 function pageload() {
     var chkPostBack = '&lt;%= Page.IsPostBack ? "true" : "false" %&gt;';

     if (chkPostBack == 'false') {

         var popup = $find('ModalPopupExtender1');
         if (popup != null) {
             popup.show();
         }

     }

 }    
</code></pre>

<p>
I got the following error, Please help me.</p>

<pre><code>The Controls collection cannot be modified because the control contains code blocks (i.e. &lt;% ... %&gt;).
</code></pre>
