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. 

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 
} 

The else Statement  

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

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 
}