Well, first off, let me stress that the book requires at least minimal knowledge of JS: variables, types, loops, the concept of arrays, etc.
Now, most JS books focus on the language itself, or building advanced codebases out of the language, or solving rather hefty use-cases. This does fit a significant need, but my book attempts to address much more direct, and well-defined, everyday concerns.
The book is entirely task-oriented, and follows a very stringent format: one page to explain the need and the code, one page to code it all. That forces us to hunker down to a very specific problem and a best-practice solution to it. But the idea is to do over 30 cases of "need to achieve this? here's how!".
Grab the free samples on the book's page : http://pragprog.com/titles/pg_js
to see for yourself what such tasks look like.
I hope you like it,