title: window.opener.document.getElementById not working
body: <p>In my asp.net web app, I create a popup window with a button.  When that button is clicked, I want to set the value of an asp:TextBox (id=TextBox1) contained in the parent window.  However, it doesn't work like all the examples I've read indicate. </p>
  
  <p>I've tried the following lines of code in my javascript onclick handler:</p>
  
  <ol>
  <li>window.opener.document.getElementById('&lt;%= TextBox1.ClientID %>').value = "abc";</li>
  <li>window.opener.document.getElementById("TextBox1").value = "abc";              </li>
  <li>window.opener.document.getElementById("ctl00_ContentPlaceHolder1_TextBox1").value = "abc";</li>
  </ol>
  
  <p>Only example 3 works.  All the stuff I've read indicates that #1 is the preferred method, but I can't seem to make it work at all.  Does anyone have any ideas what I'm doing wrong?</p>
  
  <p>I've tried this in Firefox, Chrome and IE.</p>
  
  <p>Thanks</p>