Javascript [Electronic resources] : The Definitive Guide (4th Edition) نسخه متنی

Chapter 6. Statements

As we
saw in the last chapter, expressions are JavaScript phrases that can
be evaluated to yield a value. Operators within an expression may
have side effects, but in general, expressions don't do
anything. To make something happen, you use a JavaScript

statement , which is akin to a complete sentence
or command. This chapter describes the various statements in
JavaScript and explains their syntax. A JavaScript program is simply
a collection of statements, so once you are familiar with the
statements of JavaScript, you can begin writing JavaScript programs.

Before we examine JavaScript
statements, recall from Section 2.4, that statements in JavaScript are
separated from each other with semicolons. If you place each
statement on a separate line, however, JavaScript allows you to leave
out the semicolons. Nevertheless, it is a good idea to get in the
habit of using semicolons everywhere.