The JavaScript Role-Playing Game, or JSRPG, is a legacy project I began in 1997 and no longer update. It is a full-fledged role-playing game designed entirely from scratch in JavaScript, and to my knowledge is the largest and most complex JavaScript application in existence. In addition to coding everything, I designed the game, its underlying engine, the story, and all of the maps within the game.
The most recent version of it was updated in 1999, so the introductory/disclaimer page may seem a little dated. This page is important, however, as it documents the credits for the game as well as where to get instructions for playing the game. (The game has a very thorough online tutorial that explains all of the gameplay mechanics.)