The first link you list is definitely the newest edition and the one you want. It's been updated to show the current browsers (IE7/FireFox 2) and new JavaScript uses such as Ajax. It's shorter because some of the older reference appendixes were removed to keep the book a little smaller.
The 2nd link is for an older version of the book that you won't want.
Jim Minatel
Acquisitions Director
Wiley Technology Publishing
WROX Press
Blog:
http://wroxblog.typepad.com/