Get Programming with JavaScript

Chapter 12. Conditions: choosing code to run

This chapter covers

• Comparing values with comparison operators
• Checking conditions that are true or false
• The if statement—running code only if a condition is met
• The else clause—running code when a condition is not met
• Making sure user input won’t break your code
• Generating random numbers with Math.random()

So far, all of your code follows a single path. When you call a function, every statement in the function body is executed. You’ve managed to get a lot done and covered quite a few core ideas in JavaScript but your programs have lacked flexibility; they haven’t been able to decide whether or not to execute blocks of code.

In this chapter you learn how to run code only when specified ...