Implement program flow - Programming in HTML5 with JavaScript and CSS3 - page 112

Objective 2.1: Implement program low

For the exam, you need to understand both conditional and iterative program flow. Condi-
tional program flow enables an application to examine the state of an object or variable to
decide which code path to process. The commands you use to apply the concept of condi-
tional flow are the if…else statement, the switch statement, and the ternary operator.

This objective covers how to:
■ Evaluate expressions, including using switch statements, if/then statements, and
operators
■ Work with arrays
■ Implement special types of arrays
■ Use advanced array methods
■ Implement iterative control flow

Evaluating expressions
To use a conditional flow statement, you must evaluate some data against some condition,
which you do by using conditional operators. You can use logical operators to combine
conditional operators. Combining operators is useful when more than one condition must
be met—or at least one condition from a set of conditions must be met—before processing
specific logic. Table 2-1 outlines the available operators.

TABLE 2-1 Conditional and logical operators

Operator Type Description

> Conditional Evaluates whether the value on the left is greater than the value on the right

< Conditional Evaluates whether the value on the right is greater than the value on the left

>=,<= Conditional Evaluates the same as > or < but with the additional logic that the values can

also be equal

!= Conditional Evaluates whether the values aren't equal

== Conditional Evaluates whether the values are equal independent of the underlying data type

=== Conditional Evaluates whether the values are equal both in value and underlying data type

&& Logical The AND logical operator, in which the expressions on both sides must

evaluate to true

|| Logical The OR logical operator, in which at least one expression on either side must

evaluate to true