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JavaScript - Operators

What is an operator?

Let us take a simple expression 4 + 5 is equal to 9. Here 4 and 5 are called operands and ‘+’ is called the operator. JavaScript supports the following types of operators.

Lets have a look on all operators one by one.

Arithmetic Operators

JavaScript supports the following arithmetic operators −

Assume variable A holds 10 and variable B holds 20, then −

Sr.No Operator and Description
1

+ (Addition)

Adds two operands

Ex: A + B will give 30
2

- (Subtraction)

Subtracts the second operand from the first

Ex: A - B will give -10
3

* (Multiplication)

Multiply both operands

Ex: A * B will give 200
4

/ (Division)

Divide the numerator by the denominator

Ex: B / A will give 2
5

% (Modulus)

Outputs the remainder of an integer division

Ex: B % A will give 0
6

++ (Increment)

Increases an integer value by one

Ex: A++ will give 11
7

-- (Decrement)

Decreases an integer value by one

Ex: A-- will give 9

Note − Addition operator (+) works for Numeric as well as Strings. e.g. "a" + 10 will give "a10".

Example

The following code shows how to use arithmetic operators in JavaScript.

<html>
    <body>
    <script type="text/javascript">
         var a = 33;
         var b = 10;
         var c = "Test";
         var linebreak = "<br />";
        
         document.write("a + b = ");
         result = a + b;
         document.write(result);
         document.write(linebreak);
        
         document.write("a - b = ");
         result = a - b;
         document.write(result);
         document.write(linebreak);
        
         document.write("a / b = ");
         result = a / b;
         document.write(result);
         document.write(linebreak);
        
         document.write("a % b = ");
         result = a % b;
         document.write(result);
         document.write(linebreak);
        
         document.write("a + b + c = ");
         result = a + b + c;
         document.write(result);
         document.write(linebreak);
        
         a = ++a;
         document.write("++a = ");
         result = ++a;
         document.write(result);
         document.write(linebreak);
        
         b = --b;
         document.write("--b = ");
         result = --b;
         document.write(result);
         document.write(linebreak);
            </script>                
    Set the variables to different values and then try...
    </body>
</html>

Output

   a + b = 43
   a - b = 23
   a / b = 3.3
   a % b = 3
   a + b + c = 43Test
   ++a = 35
   --b = 8
   Set the variables to different values and then try...
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