JavaScript : Object-Oriented Programming

Conditions and loops

Conditions provide a simple but powerful way to control the flow of code execution. Loops allow you to perform repetitive operations with less code. Let's take a look at:

• if conditions
• switch statements
• while, do-while, for, and for-in loops

Note

The examples in the following sections require you to switch to the multiline Firebug console. Or, if you use the WebKit console, use Shift + Enter instead of Enter to add a new line.

The if condition

Here's a simple example of an if condition:

var result = '', a = 3;
if (a > 2) {
  result = 'a is greater than 2';
}

The parts of the if condition are:

• The if statement
• A condition in parentheses—"is a greater than 2?"
• A block of code wrapped in {} that executes if the condition is satisfied

The condition ...