I've got an editor in javascript on my webpage and I would like to ask user if he/she wants to leave the page even if there are unsaved changes.

I know I can add custom message to the "onbeforeunload dialog" this way:

window.onbeforeunload = function() {
  return 'You have unsaved changes!';
}

(Source) but I want to display the dialog only where there really are some unsaved changes. How to do that?

Thanks!

I've got an editor in javascript on my webpage and I would like to ask user if he/she wants to leave the page even if there are unsaved changes.

I know I can add custom message to the "onbeforeunload dialog" this way:

window.onbeforeunload = function() {
  return 'You have unsaved changes!';
}

(Source) but I want to display the dialog only where there really are some unsaved changes. How to do that?

Thanks!

• javascript
• onbeforeunload

Share Improve this question Follow edited May 23, 2017 at 11:45 CommunityBot 111 silver badge asked Apr 18, 2010 at 19:59 MartyIXMartyIX 28.7k3232 gold badges139139 silver badges217217 bronze badges

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1 Answer 1

Sorted by: Reset to default 9

You can do something like this:

var unsavedChanges = false;
window.onbeforeunload = function() {
  if (unsavedChanges) return 'You have unsaved changes!';
}

function makeSomeChange() {
  // do some changes....
  unsavedChanges = true;
}

You can make sure to change unsavedChanges in the 'change' event handlers.