How to ask a person if they want to close a window?

Question

Possible Duplicate:
Javascript To Get An Alert When Closing The Browser Window

I have a legitimate reason for asking this, I have a web app that manages a large database and the pages for modifying lookup tables pop up in separate windows. I would like be able to remind users if there are changes they have made to the form that haven't been saved to the database, and give them the option to do so, even if they click the "X" to close the window. Is this possible?

http://stackoverflow.com/questions/333665/javascript-to-get-an-alert-when-closing-the-browser-window — gd1, Oct 22 '12 at 07:15
http://stackoverflow.com/q/299679/1519323 duplicated here. good luck! — davepmiller, Oct 22 '12 at 07:17
that first one is beautiful, I'll get my code to check the session and we're sorted, if you make it an answer I'll select it as best :) — Kelly Larsen, Oct 22 '12 at 07:22

score 2 · Answer 1 · answered Oct 22 '12 at 07:17

This is what I do

window.onbeforeunload = function (e) {
  var e = e || window.event;
  if (allowNavigationsAwayFromPage != true)
      {
      // For IE and Firefox
      if (e) {
        e.returnValue = 'Are You Sure? Some operation is still going on';
      }

      // For Safari
      return 'Are You Sure? Some operation is still going on';

      }
};

allowNavigationsAwayFromPage is a variable right now. But I usually have a function to check this.

score 0 · Accepted Answer · answered Oct 22 '12 at 07:51

the easiest way would be this:

window.onbeforeunload = function(e)
{
    e = e || window.event;
    if (confirm('Are you sure?\nNot everything has been saved yet'))
    {
        return e;//return event object, unaltered... page will unload
    }
    if (e.preventDefault)
    {
        e.preventDefault();
        e.stopPropagation();
    }
    else
    {
        e.returnValue = false;
        e.cancelBubble = true;
    }
    return false;
};

How to ask a person if they want to close a window?

2 Answers2