Conditional Statement

Conditional Statements
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:

• if statement - use this statement to execute some code only if a specified condition is true
• if...else statement - use this statement to execute some code if the condition is true and another code if the condition is false
• if...else if....else statement - use this statement to select one of many blocks of code to be executed
• switch statement - use this statement to select one of many blocks of code to be executed

If Statement

Use the if statement to execute some code only if a specified condition is true.

Syntax

if (condition)
  {
  code to be executed if condition is true
  }

If...else Statement

Use the if....else statement to execute some code if a condition is true and another code if the condition is not true.
Syntax
if (condition)
  {
  code to be executed if condition is true
  }
else
  {
  code to be executed if condition is not true
  }

If...else if...else Statement

Use the if....else if...else statement to select one of several blocks of code to be executed.

Syntax

if (condition1)
  {
  code to be executed if condition1 is true
  }
else if (condition2)
  {
  code to be executed if condition2 is true
  }
else
  {
  code to be executed if condition1 and condition2 are not true
  }

The JavaScript Switch Statement

Use the switch statement to select one of many blocks of code to be executed.

Syntax

switch(n)
{
case 1:
  execute code block 1
  break;
case 2:
  execute code block 2
  break;
default:
  code to be executed if n is different from case 1 and 2
}