mozilla/input.mozilla.org — pull request #53 by kendroberts (2012-10-28 21:11:07+00:00)
Title: added input, cut, and paste to textarea messages

Was using keyup to know when to update the "how many characters do you
have" display. Keyup misses context menu cut/paste/undo/redo and drag &
drop changes to the textarea contents. I added input which works in
new browsers to handle all of these. keyup, cut, and paste works in
most other browser as fallback.
http://jsfiddle.net/M2qsa/222/
I had to read up on all this myself here:
http://whattheheadsaid.com/2010/09/effectively-detecting-user-input-in-javascript
(they do even more which I don't understand so don't use)