onunload is responsible for executing an instruction when the page is closed. It also causes issue with IE and AJAX. onbeforeunload is more efficient because it does not run in competition with the actual closing of the window and is triggered before onunload I know Opera used to not acknowledge onbeforeunload – not sure if … Read more
I see that it’s an old question, but i faced this problem recently. I’m using window.unload and it works fine in ios browsers (although if you look at Apple documentation it seems to be deprecated and they recommend to use document.pagehide)
Another implementation is the following you can find it in this webpage: http://ujap.de/index.php/view/JavascriptCloseHook <html> <head> <script type=”text/javascript”> var hook = true; window.onbeforeunload = function() { if (hook) { return “Did you save your stuff?” } } function unhook() { hook=false; } </script> </head> <body> <!– this will ask for confirmation: –> <a href=”http://google.com”>external link</a> <!– … Read more
The correct way to display the alert is to simply return a string. Don’t call the alert() method yourself. <script type=”text/javascript”> $(window).on(‘beforeunload’, function() { if (iWantTo) { return ‘you are an idiot!’; } }); </script> See also: https://developer.mozilla.org/en-US/docs/Web/Events/beforeunload
This bit of JavaScript works for me on Safari and Chrome on ipad and iphone, as well as desktop/laptop/other browsers: var isOnIOS = navigator.userAgent.match(/iPad/i)|| navigator.userAgent.match(/iPhone/i); var eventName = isOnIOS ? “pagehide” : “beforeunload”; window.addEventListener(eventName, function (event) { window.event.cancelBubble = true; // Don’t know if this works on iOS but it might! … } );
Using onunload allows you to display messages, but will not interrupt the navigation (because it is too late). However, using onbeforeunload will interrupt navigation: window.onbeforeunload = function() { return “”; } Note: An empty string is returned because newer browsers provide a message such as “Any unsaved changes will be lost” that cannot be overridden. … Read more
Update (2017) Modern browsers now consider displaying a custom message to be a security hazard and it has therefore been removed from all of them. Browsers now only display generic messages. Since we no longer have to worry about setting the message, it is as simple as: // Enable navigation prompt window.onbeforeunload = function() { … Read more
You can’t modify the default dialogue for onbeforeunload, so your best bet may be to work with it. window.onbeforeunload = function() { return ‘You have unsaved changes!’; } Here’s a reference to this from Microsoft: When a string is assigned to the returnValue property of window.event, a dialog box appears that gives users the option … Read more