What are the best websites to learn entry level Javascript?
www.w3schools.com has a lot of information on Javascript and DOM. They even have an online tutorials/examples that allow you to modify the example and re-run it to try out your new Javascript skills.
www.w3schools.com has great tutorials and www.jslint.com will help you learn the best practices (and save a few headaches).
Screw w3schools ... seriously.
Head to the yahoo developer network, and learn real js.
http://developer.yahoo.com/yui/theater/
And learn JS from the Crockford videos. THAT will save you time.
Websites are good but I recommend a good, solid book to have on-hand. Simply Javascript (ISBN 0-9802858-0-1) is an excellent book by Site Point. Others are Head First Javascript on O'Reilly, and DOM Scripting on Friends of ED (If manipulating browser UI is what you're looking for)
I have been using a web site recently about developing GUI's in java, which is something I wanted to learn and found this site ( http://www.macs.hw.ac.uk/guidebook/? ) After a few hours of reading and studding, I learned how to develop my first GUI, which is a code pad for security using a four digit int string to open it. The site is very easy to understand and the author gives you great code example to go by. I know there are easier ways to develop GUI's but for now I just wanted to get a basic understaning of them, and that is what this site does. It teaches you about JPanels, JLabels, and everything else you need to know to make a nice GUI. Since I started to learn Java, I found it best to use different sites, as I haven't found one single site that can teach you everything.
Sitepoint is a great website for books, articles, and blogs for everything web-related. It also has very active discussion forums.