Javascript warning before closing browser not working as expected
I tried the solution based of lots of examples and the event works only if something else is clicked first eg. a link has been first right clicked on the same page. Then if I click the browser close button it prompts a warning before closing as expected.
Otherwise if I first go to the page or refresh it and click close button it doesn't work and page closes. The code inside onbeforeunload function hits each time but in the last case clearly has no effect.
$("button, a").bind("click", function () {
window.onbeforeunload = null;
});
window.onbeforeunload = function (e) {
e = e || window.event;
// For IE and Firefox prior to version 4
if (e) {
e.returnValue = 'Sure?';
}
// For Safari
return 'Sure?'; // the code hits each time - normally it does have no effect but if right-clicked a link on the page first it does work?
};
It looks as a very strange behaviour. Anyone has idea why this works only when another event has happened on the page first?
Tried in Firefox & Chrome.
It's a feature. According to MDN:
To combat unwanted pop-ups, some browsers don't display prompts created in beforeunload event handlers unless the page has been interacted with; some don't display them at all.
What is the use case where you need the onbeforeunload popup to be shown even with no user interaction? Usually these are for preventing data loss on unsubmitted forms, for instance. If the user wants to leave the page and there isn't any reason to show the popup, you shouldn't attempt to do so.
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