Script Summary: Corrects the grammatical error on Twitter.
All credit for the code goes to Thomas Steiner (@tomayac) whose original extension at https://chrome.google.com/extensions/detail/ial... I made into a script for Firefox and other browsers.
Updated to 1.0.6 and includes https://twitter.com as well.
(An update to the new twitter layout was attempted but caused the script to become unresponsive, I am trying to fix this and will release it when I do.)