title: modalpopup extender with iframe is not working
body: <p>I am using Modal popup for displaying different page in a popup and parent page is not editable</p>
  
  <p>here is my code</p>
  
  <pre><code>&lt;asp:Button ID="btnModalPopup" runat="server" Text="" Visible="false" /&gt;
  &lt;asp:ModalPopupExtender ID="btnModalPopup_ModalPopupExtender" BehaviorID="btnModalPopup_ModalPopupExtender" runat="server" PopupControlID="ModalPopup" 
     BackgroundCssClass="ModalPopupBG" DynamicServicePath="" Enabled="True" TargetControlID="btnModalPopup"&gt; &lt;/asp:ModalPopupExtender&gt;
   &lt;div id="ModalPopup" runat="server"&gt;
   &lt;iframe id="iframePopup" runat="server" width="700" scrolling="yes" height="500"&gt;&lt;/iframe&gt;
  &lt;/div&gt;
  </code></pre>
  
  <p>and code behind</p>
  
  <pre><code>iframePopup.Attributes.Add("src", "default.aspx");
  btnModalPopup_ModalPopupExtender.Show();
  </code></pre>
  
  <p>But the iframe is showing in the main page not a popup please any body can help me</p>