Learning JavaScript

Chapter 1. Introduction and First Looks

JavaScript is one of the most widely used programming languages; it is also one of the most misunderstood. Its growth has exploded in the last few years, and most web sites use it in some form. Its component-based capabilities simplify the creation of increasingly complicated libraries—most providing effects in web pages that previously required the installation of an external application. It can also be tightly integrated with server-side applications that are created with a variety of languages and interface with any number of databases. Yet for all of this, JavaScript is often considered lightweight and unsophisticated—not like a “real” programming language.

In some ways, JavaScript is too easy to use. To its detractors, it lacks discipline; its object-oriented capabilities aren’t really OO; it exists within a simplified environment with only a subset of functionality; it isn’t secure; it’s loosely typed; it doesn’t compile into bytes or bits. I remember reading in a JavaScript introduction years ago that you shouldn’t let the name fool you: JavaScript has little to do with Java. After all, Java is hard to learn.

So what’s the reality? Is JavaScript a fun little scripting language—lightweight, helpful, but not to be taken seriously? Or is it a powerful programming language you can trust with some of your site’s most important functionality? The reality of JavaScript, and hence the confusion, is that it’s two languages in one.

The first is ...