title: Microsoft JScript runtime error: Sys.WebForms.PageRequestManagerServerErrorException: The status code returned from the server was: 500
body: <p>My error is </p>
  
  <blockquote>
    <p>Microsoft JScript runtime error: Sys.WebForms.PageRequestManagerServerErrorException: An unknown error occurred while processing the request on the server. The status code returned from the server was: 500</p>
  </blockquote>
  
  <p>I have an <code>UpdatePanel</code>, and a <code>GridView</code> in it, and several <code>TextBox</code>es on my webpage.In my gridview there are product informations, when I set the <code>SelectedIndex</code> of my gridview as -1 for the start.</p>
  
  <p>I run the code, and select a product from the gridview, it works fine.Then I click to another product on the gridview(meaning the selected index is changed) then I get the error at the top of my question.</p>
  
  <p>A day ago, Infragistics tabs were used in this webpage for <code>Tabs</code>, this error wasn't appearing, I am using Ajax <code>TabContainer</code> now but I can't seem to handle this error.I tried adding  <code>ValidateRequest="false"</code> to my Page directive but that didn't work out.</p>
  
  <p>Any ideas?Anybody encountered with this kind of error and solved?</p>
  
  <p>Thank you in advance.</p>