Overview of JavaScript Environments

So far in our journey, we've only been exposed to the modern web browser as a JavaScript runtime, but even within browsers, there are a variety of JavaScript engines that serve as different runtimes for JavaScript. For instance, Chrome has the V8 engine, while Firefox runs JavaScript through SpiderMonkey. Just about every browser has its own distinct engine.

There are also other runtimes aside from those that are browser-based. We'll have a look at the variety of runtimes available to us now.

Browser-Based JavaScript

By far, the most common environment for using JavaScript throughout its entire history as a language is within the web browser. We've already spoken of this particular runtime quite a lot, so we will not spend time going over all of this again:

Figure 2.20: V8—JavaScript in the web browser

Some of the benefits of using the web browser as a JavaScript runtime are as follows:

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