title: confirm() cancel button no longer working in IE11
body: <p>I have an asp.net 4 site that I am using javascript's confirm() method before a user deletes an object from the database as a client based confirmation. With IE6-10, Firefox, Chrome, and Safari this works well. I click on cancel and it stops the page loading. However I been having problems using this on a usercontrol with IE11.</p>
  
  <p>The usercontrol loads a datagrid which has an link button that gets the server to call a delete stored procedure.</p>
  
  <p>With IE11, the Confirm popup opens, but if I click the cancel button or x on the window does not stop the page posting and calling the delete command in the server. I tried everything I can think off, but it just always passes and reads the page as valid.</p>
  
  <p>In the code behind of the ItemDataBound we have this...</p>
  
  <pre><code>DeleteButton.CommandArgument = ac.ID.ToString(); //set the id so we know what to delete
  DeleteButton.Attributes.Add("onclick", "Sure(event)");
  </code></pre>
  
  <p>This attaches the javascript to the image button.</p>
  
  <p>Then in the file that contains the javascript we have the following code...</p>
  
  <pre><code>function Sure(evt){
  var ans = confirm("Are you sure you want to delete? \n\nPress OK to continue or Cancel to stop.");
  if(!ans){
      var e = (window.event)? window.event:evt;
      e.returnValue = false;
      return false;
  }
  }
  </code></pre>
  
  <p>Debugging, it is setting the values to false and returning them when I press the cancel button, but this isn't stopping the postback like every other browser does. It goes straight to the call for the database to delete it.</p>
  
  <p>Any idea why IE11 wouldn't stop the postback after confirm was cancelled?</p>