This site hosts a free tutorial completely for the Beginners. The tutorial is very interactive and they have covered almost everything from handling variables, operators or basic syntaxes to handling objects, form data. In this tutorial I have found that they also have tought how to create basic interactive stuffs like slideshows, rollover and accessing menus or cookies. In one word the tutorial is totally “complete” tutorial. But to understand each example you must know HTML.
This site hosts another tutorial for absolute beginners. The tutorial is broken into two sections basic and advanced. The basic section covers all the basic concept like variables, operators, control statements etc. and the advanced section covers the advanced stuffs. Lots of useful examples are given in order to brush up your knowledge. Still it is recommonded that the first two tutorials should be consulted before you use this site. Though this site has all the references which you’ll require when you will start the development.