Setting onbeforeunload on body element in Chrome and IE using jQuery

Question

I have a system where I want to check with the user if they're sure they want to leave the page once a dirty flag is set.

I'm using the following code - In FireFox, I can look at the page source through FireBug and the tag correctly has the onbeforeunload attribute inserted in it.

In Chrome and FireFox, this doesn't happen though and I'm able to navigate away from the page without any warning at all. The jQuery line to update the body tag is definitely being executed, it just isn't performing it.

if ($("body").attr('onbeforeunload') == null) {
    if (window.event) {
        // IE and Chrome use this
        $("body").attr('onbeforeunload', 'CatchLeavePage(event)');
    }
    else {
        // Firefox uses this
        $("body").attr('onbeforeunload', 'return false;CatchLeavePage(event)');
    }
}

Any ideas how to proceed from here?

Suggestion

I was able to use $("body").css("margin", "50px"); and $("body").attr("test", "hello"); it just seems that I can't set the onbeforeunload attribute now... – Suggestion

Answer 1

you cannot abort page unload by returning false. you must return string that will be shown to user in a message box, and he decides if he want to leave or stay on the page (by selecting either 'OK' or 'Cancel' button), so you need to write your code like this:

 window.onbeforeunload = function() {
    return "Are you sure you want to leave this page bla bla bla?"; // you can make this dynamic, ofcourse...
 };

Titus

Answer 2

try this

  <script type=\"text/javascript\">
        var dont_confirm_leave = 0; //set dont_confirm_leave to 1 when you want the user to be able to leave withou confirmation
        var leave_message = 'You sure you want to leave?'
        function goodbye(e) 
        {
            if(dont_confirm_leave!==1)
            {
                if(!e) e = window.event;
                //e.cancelBubble is supported by IE - this will kill the bubbling process.
                e.cancelBubble = true;
                e.returnValue = leave_message;
                //e.stopPropagation works in Firefox.
                if (e.stopPropagation) 
                {
                    e.stopPropagation();
                    e.preventDefault();
                }

                //return works for Chrome and Safari
                return leave_message;
            }
        }   
    window.onbeforeunload=goodbye;
    </script>

Tinstone

Omg omg! You saved my day. It seems that krcko is wrong with his assumption: "You cannot abort page unload by returning false". Or he's not precise enough. It looks that (with IE only) if the "onbeforeload" event returns false, nothing is displayed. So the code I'm working on was returning false, and no message with IE, but always a message displaying "false", and asking to leave. Your solution works for all browsers. (Thank you)³². – Consideration

Answer 3

window.onbeforeunload = function () { return 'Are you sure?' };

Des

Answer 4

Check this code :

var validNavigation = false;

function wireUpEvents() {
var dont_confirm_leave = 0; 
var leave_message = "You sure you want to leave ?";

function goodbye(e) {
if (!validNavigation) {
if (dont_confirm_leave !== 1) {
if (!e) e = window.event;
e.cancelBubble = true;
e.returnValue = leave_message;
//e.stopPropagation works in Firefox.
if (e.stopPropagation) {
e.stopPropagation();
e.preventDefault();
}
//return works for Chrome and Safari
return leave_message;
}
}
}

window.onbeforeunload = goodbye;

document.onkeydown = function () {
switch (event.keyCode || e.which) {
case 116 : //F5 button
validNavigation = true;
case 114 : //F5 button
validNavigation = true;
case 82 : //R button
if (event.ctrlKey) {
validNavigation = true;
}
case 13 : //Press enter
validNavigation = true;
}

}
// Attach the event click for all links in the page
$("a").bind("click", function () {
validNavigation = true;
});

// Attach the event submit for all forms in the page
$("form").bind("submit", function () {
validNavigation = true;
});

// Attach the event click for all inputs in the page
$("input[type=submit]").bind("click", function () {
validNavigation = true;
});
}

// Wire up the events as soon as the DOM tree is ready
$(document).ready(function () {
wireUpEvents();
});

Viviennevivify

Answer 5

It's not pretty, but it did the trick.

var warnclose = true;
var warn = function(e) {
    var warning = 'Your warning message.';
    if (warnclose) {
        // Disables multiple calls
        warnclose = false;

        // In case we still need warn to be called again 
        setTimeout(function(){
            warnclose = true;
        }, 500);

        return warning;
    }
};
window.onbeforeunload = warn;

Calvados