Capture The Result Of Window.onbeforeunload

I have a scenario, I have to save the changes when user clicks yes on window.onbeforeunload for that I need to submit the form and nothing should be happen when selected no. Any he

Solution 1:

You cannot use your own dialog in onbeforeunload. The only thing you can do is return a string to be displayed (on some browsers). You cannot stop the browser from leaving, only the user can control that.

What you can do is the following:

window.onbeforeunload = function(){
    return 'Are you sure you want to leave this page?';
};

This will ask the user if they want to leave or not. Then you can use the onunload event to run a function when they leave. From there, you can make a "synchronous" AJAX request to submit the form.

window.onunload = function(){
    var request = new XMLHttpRequest();
    request.open('POST', '/SREPS/read.do', false);
    request.setRequestHeader('Content-type', 'application/x-www-form-urlencoded');

    request.send(new FormData(readForm));
};

If you are using jQuery, you can do:

window.onunload = function(){
    $.ajax({
        url: '/SREPS/read.do',
        type: 'post',
        async: false,
        data: $(readForm).serialize()
    });
};