Comment Box Mechanism Development

We want someone to fix a simple comment box mechanism alike that of Twitter where someone writes something in a comment box, with a maximum of 120 characters. While the user writes the comment and the characters augment, the maximum left characters number should appear on the top left corner just over the comment box. The opposite should happen if the user deletes characters.? 1. A user should not be let to post when characters exceed appointed maximum. 2. A user should not be let to post any links. Everything starting with http:// and www. should be stripped out of the comment. 3. A user should not be let to post any links containing bad words. Bad words should be stripped out with asterisks (***) based on an external vocabulary All posts from the comment box should appear instantly underneath the comment box in a separate table or div you must create - which must be easy to modify if needed.