Alert User on Abnormal Close of CRM form Window

The Below Code will Popup the alert when you close the form without saving the changes made in that.

/* Code to Alert User On Abrupt Close of a Window */

window.onbeforeunload =
function () {
    if (document.getElementById("IFRAME_QueryXML").contentWindow.window.ispagedirty) {
        event.returnValue = "Changes made to Conditions will be lost!";
        return false;
    }
};