What does "e" mean? When reading JavaScript tutorials

Hi
I have started reading a tutorial on a highly respected site called “http://www.quirksmode.org” in this tutorial the author passes the parameter “e” in a slew of functions like you are supposed to know what “e” means. So what does it mean? The link to the article I am talking about is here.
I would appreciate an answer
Marc

“e” is a common abbreviation of the “event” parameter. For details see his other page http://www.quirksmode.org/js/introevents.html , section “Accessing the event”.