It was once said, "JavaScript is the only language developers don't learn to use before using it."
I laugh each time I hear that quote because it was true for me and I suspect it was for many other developers. JavaScript, and maybe even CSS and HTML, were not a core computer science language taught at college in the Internet's early days, so personal development was very much based on the budding developer's search and "view source" abilities to piece together these basic web languages.
I still remember my first high school website project. The task was to create any type of web store, and me being a James Bond fan, I decided to create a Goldeneye store. It had everything: the Goldeneye midi theme song playing in the background, a JavaScript-powered crosshairs following the mouse around the screen, and a gunshot sound that played upon every click. Q would have been proud of this masterpiece of a website.
I tell that story because I did back then what many developers are doing today: I copied and pasted chunks of JavaScript code into my project without having a clue what's actually happening. The widespread use of JavaScript toolkits like jQuery have, in their own small way, perpetuated this pattern of nonlearning of core JavaScript.
I'm not disparaging JavaScript toolkit use; after all, I'm a member of the MooTools JavaScript team! But the reason JavaScript toolkits are as powerful as they are is because their developers know the fundamentals, and their "gotchas," and apply them magnificently. As useful as these toolkits are, it's still incredibly important to know the basics of the language, and with books like Kyle Simpson's You Don't Know JS series, there's no excuse not to learn them.
Types and Grammar, the third installment of the series, is an excellent look at the core JavaScript fundamentals that copy and paste and JavaScript toolkits don't and could never teach you. Coercion and its pitfalls, natives as constructors, and the whole gamut of JavaScript basics are thoroughly explained with focused code examples. Like the other books in this series, Kyle cuts straight to the point: no fluff and word-smithing -- exactly the type of tech book I love.
Enjoy Types and Grammar and don't let it get too far away from your desk!
David Walsh
http://davidwalsh.name, @davidwalshblog
Senior Web Developer, Mozilla