Ivo Wetzel covers some of the quirks of the JavaScript language. Some of these cause subtle bugs, some overturn conventional wisdom. It covers toString on numbers. Covers the advanced JavaScript features such as prototypal inheritance, this, closures, anonymous wrappers, type-casting, automatic semicolon insertion and hoisting of function and variable declarations.
Angus Croll takes the reader step-by-step through some basic JavaScript code explaining what 'this' is in each step and why. He explains how 'this' depends on the execution context, and how it is manipulated by how JavaScript functions are called (or applied or bound with bind), and how Constructors create a new context.
An explanation of scope in terms of an execution context and scope chain. Also describes how we can alter the this reference using apply and call.