JavaScript for Web Designers

Chapter 3. Conditional Statements

CONDITIONAL STATEMENTS are a type of control flow concerned with logic: they determine when and where to execute code, based on conditions you specify.

if/else STATEMENTS

Conditional statements are almost entirely some variation on “given X, do Y.” The most common example of this—and one nearly ubiquitous in terms of any programming language—is the if/else statement. Saying “if this, do that” is about as uncomplicated as a logical statement gets, but by the end of this chapter you’ll see how something so simple on the surface can make up the lion’s share of logic in our scripts.

if

In its most ...