You have now completed the introduction to the fundamental concepts related to functions in JavaScript. You've been laying the groundwork that will allow you to quickly grasp the concepts of object-oriented JavaScript and the patterns that are in use in modern JavaScript programming. So far, we've been avoiding the OO features, but as you have reached this point in the book, it is only going to get more interesting from here on in. Let's take a moment and review the topics discussed in this chapter:
The basics of how to define and invoke (call) a function
Function parameters and their flexibility
Built-in functions—
parseInt(),parseFloat(),isNaN(),isFinite(),eval(), and the four functions to encode/decode a URLThe scope of variables in JavaScript—no curly braces scope, variables have only function scope; functions have lexical scope and follow a scope chain
Functions as data—a function is like any other piece of data that you assign to a variable and a lot of interesting applications...