Firefox 4 onBeforeUnload custom message

Question

In Firefox 3, I was able to write a custom confirmation popup with:

window.onbeforeunload = function() {
   if (someCondition) {
      retur         


        

Answer 1

Addition to the above Answer, I have improved the workaround.

I have used jquery here. you can use default javascript funciton as well.

$(window).bind('beforeunload', function() {
    if(/Firefox[\/\s](\d+)/.test(navigator.userAgent) && new Number(RegExp.$1) >= 4) {
        if(confirm("Are you Sure do you want to leave?")) {
            history.go();
        } else {
            window.setTimeout(function() {
                window.stop();
            }, 1);
        }
    } else {
        return "Are you Sure do you want to leave?";
    }
});

Tested and working in firefox 11 as well. :)