When using window.onbeforeunload (or $(window).on("beforeunload")), is it possible to display a custom message in that popup?
Maybe a small trick that works on major browsers?
By looking at existing answers I have the feeling this was possible in the past using things like confirm or alert or event.returnValue, but now it seems they are not working anymore.
So, how to display a custom message in the beforeunload popup? Is that even/still possible?
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Answer
tl;dr – You can’t set custom message anymore in most modern browsers
A quick note (since this is an old answer) – these days all major browsers don’t support custom message in the
beforeunloadpopup. There is no new way to do this. In case you still do need to support old browsers – you can find the information below.
In order to set a confirmation message before the user is closing the window you can use
jQuery
$(window).bind("beforeunload",function(event) {
return "You have some unsaved changes";
});
Javascript
window.onbeforeunload = function() {
return "Leaving this page will reset the wizard";
};
It’s important to notice that you can’t put confirm/alert inside beforeunload
A few more notes:
- NOT all browsers support this (more info in the Browser compatibility section on MDN) 2. In Firefox you MUST do some real interaction with the page in order for this message to appear to the user.
3. Each browser can add his own text to your message.
Here are the results using the browsers I have access to:
Chrome:
Firefox:
Safari:
IE:
Just to make sure – you need to have jquery included
More information regarding the browsers support and the removal of the custom message: