title: Detecting form changes on beforeunload?
body: <p>This has already been asked, I know, but I don't understand why this isn't working for me.</p>
  
  <p><a href="http://jsfiddle.net/M9tnP/16/" rel="nofollow">http://jsfiddle.net/M9tnP/16/</a></p>
  
  <p>Trying to detect form changes, and if the user tries to navigate away, I want them to confirm that they will lose their changes...</p>
  
  <pre><code>var dirty = false;
  $("form#add_item :input").change(function() {
      dirty = true;
  });
  
  $("window").on('beforeunload', function() {
      if (dirty) {
          return 'You have unsaved changes! If you leave this page, your changes will be lost.';
      }
  </code></pre>
  
  <p>});​</p>