Prompt confirm before Leaving edited html form

Question

If user tries to leave unsaved edited form, a message box pop-up

\"This page is asking you to confirm that you want to leave - data you have entered may not be saved. Le

Answer 1

You could use the "onbeforeunload" event. The syntax is as follows:

window.onbeforeunload = function () {
    return "Your text string you want displayed in the box";
}

This event will popup that confirmation dialog that you described above asking whether or not the user truly wants to leave the page.

Hope this helps.