how can i prevent onbeforeunload from firing when a certain condition is met?
<p>i have a page on which i want to confirm if the user wants to leave.
i have to confirm only when a certain condition is met so i wrote code like this</p>

<pre><code>var back=false;
back=//check if user pressed back button
window.onbeforeunload = function (e) {
    alert(back);   //this alerts true
    if(back==true)
        return false;
        //e.preventDefault;   --this does not work too
};
</code></pre>

<p>but this does not work. i mean when i click on back button this onbeforeunload still fires and i still get the confirmation message even when i m returning false.Whats can be wrong?
Thanks </p>
