var myEvent = window.attachEvent || window.addEventListener;
       var chkevent = window.attachEvent ? 'onbeforeunload' : 'beforeunload'; /// make IE7, IE8 compitable

       myEvent(chkevent, function(e) { // For >=IE7, Chrome, Firefox
           var confirmationMessage = 'Are you sure to leave the page?';  // a space
           (e || window.event).returnValue = confirmationMessage;
           return confirmationMessage;
       });

I have used the following code: var myEvent = window.attachEvent || window.addEventListener; var chkevent = window.attachEvent ? 'onbeforeunload' : 'beforeunload'; /// make IE7, IE8 compitable myEvent(chkevent, function(e) { // For >=IE7, Chrome, Firefox var confirmationMessage = 'Are you sure to leave the page?'; // a space (e || window.event).returnValue = confirmationMessage; return confirmationMessage; });