Conditional Statements

Conditional statements are used to perform different actions based on different conditions.

Very often when you write code, you want to perform different actions for different decisions.

You can use conditional statements in your code to do this.

In JavaScript we have the following conditional statements:

Use if to specify a block of code to be executed, if a specified condition is true

Use else to specify a block of code to be executed, if the same condition is false

Use else if to specify a new condition to test, if the first condition is false

Use switch to specify many alternative blocks of code to be executed


The if Statement

Use the if statement to specify a block of JavaScript code to be executed if a condition is true.

Syntax:

if (condition) {
  //  block of code to be executed if the condition is true
}

Note that if is in lowercase letters. Uppercase letters (If or IF) will generate a JavaScript error.

In below Example:

Make a "Good day" greeting if the hour is less than 18:00:

EXAMPLE ❯


The else Statement

Use the else statement to specify a block of code to be executed if the condition is false.

if (condition) {
  //  block of code to be executed if the condition is true
else {

  //  block of code to be executed if the condition is false
}

Example:

If the hour is less than 18, create a "Good day" greeting, otherwise "Good evening":

EXAMPLE ❯


The else if Statement

Use the else if statement to specify a new condition if the first condition is false.

Syntax:

if (condition1) {
  //  block of code to be executed if condition1 is true
else if (condition2) {

  //  block of code to be executed if the condition1 is false and condition2 is true
else {

  //  block of code to be executed if the condition1 is false and condition2 is false
}

EXAMPLE ❯