JavaScript If-else

The JavaScript if-else statement is used to execute the code whether condition is true or false. There are three forms of if statement in JavaScript.

1. If Statement
2. If else statement
3. if else if statement

JavaScript If statement

It evaluates the content only if expression is true. The signature of JavaScript if statement is given below.

if(expression){  

//content to be evaluated  

}  

JavaScript If...else Statement

It evaluates the content whether condition is true of false. The syntax of JavaScript if-else statement is given below.

JavaScript Switch

The JavaScript switch statement is used to execute one code from multiple expressions. It is just like else if statement that we have learned in previous page. But it is convenient than if..else..if because it can be used with numbers, characters etc.

The signature of JavaScript switch statement is given below.

switch(expression){  

case value1:  

 code to be executed;  

 break;  

case value2:  

 code to be executed;  

 break;  

......  

  

default:   

 code to be executed if above values are not matched;  

}  

Let’s see the simple example of switch statement in javascript.

<script>  
var grade='B';  
var result;  
switch(grade){  
case 'A':  
result="A Grade";  
break;  
case 'B':  
result="B Grade";  
break;  
case 'C':  
result="C Grade";  
break;  
default:  
result="No Grade";  
}  
document.write(result);  
</script>