detect back button click in browser
<p>I have to detect if a user has clicked back button or not.
For this I am using </p>

<pre><code>window.onbeforeunload = function (e) {
}
</code></pre>

<p>It works if a user clicks back button.  But this event is also fired if a user click F5 
or reload button of browser.  How do I fix this?</p>
