The Book of JavaScript, 2nd Edition

Event

The event object describes an event that just happened: a mouse click, a cursor movement, and so on. See Chapter 13 for more details.

Properties

altKey	FF, IE 4	true if the ALT key is held down
button	FF, IE 4	If the event involves a click, this says what kind. A 2 means the right button was clicked. Some other number probably means the left button. See Chapter 13 for more information.
clientX	IE 4	x coordinate of an event in a window
clientY	IE 4	y coordinate of an event in a window
ctrlKey	FF, IE 4	true if the CTRL key is held down
keyCode	FF, IE 4	ASCII value of the key that was pressed
pageX	FF	x coordinate of an event in a window
pageY	FF	y coordinate of an event in a window
screenX	FF, IE 4	x coordinate of an event on the screen
screenY	FF, IE 4	y coordinate of ...