title: Chrome/Safari not calling unload in some cases
body: <p>Have been stuck with this issue for a few days now, and really need, and would appreciate some help. My requirement is that I want to make a server side callback to clear off some objects when the user navigates away from our page, without clicking logout. For business reasons, our ASP.NET session timeout has to be set to a very high value. Further, I do not want to popup a alert/dialog to force the user to return to the page and click Logoff.</p>
  
  <p>The solution I have arrived at thus far is to make a AJAX callback by embedding this javascript in the page.</p>
  
  <pre><code>window.onunload = pageleave;
       function pageleave() {                  
                    alert('test');
                    PageMethods.CheckLogout('abc','xyz',OnSucceed,OnFail);                  
        }     
  </code></pre>
  
  <p>Here is the problem though : 
  For IE and Firefox, the unload fires, the alert is seen, and I see the callback on my C# side in all the cases I desire</p>
  
  <pre><code>    a)  User closes browser 
      b)  User types in a new URL in the address bar 
      c)  User clicks on a link causing page to reload
  </code></pre>
  
  <p>For Chrome and Safari, cases a and b work fine. However, when the user clicks on a link, which causes my aspx page to reload, my C# side code is not invoked. The javasacript alert is fired though.</p>
  
  <p>I am trying to see how I can get Chrome/Safari to behave like IE/Firefox. Is this even a possibility?</p>
  
  <p>Thanks in advance for the help,</p>
  
  <p>Rajesh.</p>