Introduction

JavaScript is a language with interesting beginnings. In its early days, it was not taken very seriously—the only widely accepted, functionally correct use for the language was to perform client-side validation of form data. Many developers only copied and pasted simple code snippets that performed a single action on a website they were building. All these code snippets did were very simple actions such as reveal an alert to the user or provide a date countdown—simple logic.

Today, JavaScript is a whole different beast—and one with the power to literally build out entire HTML documents, revise CSS styling on the fly, and securely transport and interpret data from various remote sources. Whereas in times past, HTML was the primary technology on the web, in the present era, JavaScript is king.

Any introduction to JavaScript requires a foundational background of the history and origins of the language in order to move forward and achieve competency. This chapter introduces us to JavaScript, from its history to modern implementations. It also provides us with additional information on various uses of the language so that we can provide a proper context for what comes next.