Auto responding chat box for my page

I am looking to insert an auto responding chat box into my page. I have an example of the kind of format i would like. I would like to be able to change the script in the autoresponder whenever I wanted, simply. I do not want it to spit out the whole script at one time, I need to be able to insert sentences and links. I would prefer if you could throw in keywords, but will accept if it doesn't.