CHAPTER 1 ■ JAVASCRIPT YOU NEED TO KNOW
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In this case, the file is called myScript.js, and it resides in a directory named scripts. You can also write your
script directly in the HTML file itself. Listing 1-2 demonstrates this technique.
Listing 1-2. Using an Inline Script
<!DOCTYPE html>
<html>
<head>
<title>JavaScript Primer</title>
</head>
<body>
<!-- an inline script -->
<script>console.log("Hello");</script>
</body>
</html>
Most of the time, it is better to use the first approach and reference a separate file containing your scripts. This
way, you can reuse the same scripts in multiple files. The second method, usually referred to as an inline script, is
most often used when reuse isn’t a requirement, or simply for convenience.
Assuming that the file script.js contains the exact same code as the inline script, the browser output would be
as follows:
Hello
For the most part, I will include complete code listings in this chapter, so that you can load them into your
browser and experiment. You will learn a lot more by tinkering with code and viewing its output than by relying solely
on this drive-by introduction.
Statements
A JavaScript application is essentially a collection of expressions and statements. Without the aid of other constructs,
such as branching and looping statements, which I will discuss shortly, these are executed by the browser, one after
the other. Each usually exists on its own line and, optionally, ends with a semicolon (see Listing 1-3).
Listing 1-3. Statement Execution
<!DOCTYPE html>
<html>
<head >
<title>JavaScript Primer</title>
<script>
console.log("I am a statement");
console.log("I am also a statement");
</script>
</head>
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