JavaScript Tutorial

This JavaScript tutorial is crafted for beginners to introduce them to the basics and advanced concepts of JavaScript. By the end of this guide, you'll reach a proficiency level that sets the stage for further growth. Aimed at empowering you to progress towards becoming a world-class software developer, this tutorial paves the way for a successful career in web development and beyond.

Arithmetic Operators
JavaScript Arithmetic Operators
Arithmetic operators in JavaScript perform mathematical calculations on numeric values (operands). Most of the arithmetic operators are binary operators as they perform calculations on two operands. Some arithmetic operators are unary operators. The unary operators perform computation on a single operand.
JavaScript supports many arithmetic operators such as addition, subtraction, multiplication, division operators, etc. It uses the common symbols for arithmetic operators such as "+" for addition, "-" for subtraction, "*" for multiplication, "/ " for division etc.
The operands can be literals, variables or the expression.
var z = 3 + 5;  // 3 and 5 are literal values.
const x = 3; y = 5;
var z = x + y ; // x and y are variables. 
var z = 3 + 2*x  // expression
In general, arithmetic operators are used to perform mathematical operations but they can be used for other operations as well. For example, the addition operator (+) can be used for string concatenation.
Here, we have given a table containing the mathematical operators and explaining the functionality of each operator.
Operator
Name
Description
+
Addition
Adds two operands
-
Subtraction
Subtracts the second operand from the first
*
Multiplication
Multiply both operands
/
Division
Divide the numerator by the denominator
%
Modulus
Outputs the remainder of an integer division
++
Increment
Increases an integer value by one
--
Decrement
Decreases an integer value by one
Let's discuss the different operators with the help of examples.
JavaScript Addition (+) Operator
The JavaScript addition (+) operator adds two numeric operands. It is denoted by the plus (+) symbol.
var x = 5, y = 10;
var sum = x + y;
This operator can also be used to concatenate strings and/or numbers.
var z = '10' + 3  // returns 103
var z = '10' + '3'  // returns 103
If one operand is string, the addition operator converts the other operand to string and concatenate it with first operand.
If both the operands are string, it just concatenates the second operand to the first operand.
If both operands are numeric values, it will return the numeric value.
Example
In the below example, we demonstrate adding two decimal numbers and concatenating the strings and numbers.
<html>
<body>
   <script>
      const x = 3; y = 5;
      var z = x + y ;
      document.write(z +"</br>");
      var z = '10' + 3 
      document.write(z +"</br>");
      var z = '10' + '3';
      document.write(z +"</br>");
   </script>
</body>
</html>
JavaScript Subtraction (-) Operator
JavaScript subtraction (-) operator subtracts the right operand from the left operand and produces their difference. It is denoted by the minus (-) symbol.
20 - 10; // returns 10
'20' - 10; // returns 10
'20' - '10'; // returns 10
'20ee' - 10; // returns NaN
NaN - 10 // return NaNs
Infinity - 10 // returns infinity
The subtraction operator uses numeric operands but can also be used for non-numeric operands such as strings.
If both operands are numbers, then resultant is number.
If any or both operands are strings (containing only numbers), it first converts the strings to number and then performs subtraction operations.
If string contains non numeric value, it will return NaN.
If any operand is NaN or Infinity, the result will be NaN or Infinity respectively.
Example
In the below example, we demonstrate the subtraction two decimal numbers and of other datatypes.
<html>
<body>
   <script>
      var x = 20; y = 10;
      var z = x - y ;
      document.write(z +"</br>");
      x = "20"; y = "10"
      z = x - y ;
      document.write(z +"</br>");
      x = "20ee"; 
      z = x - y ;
      document.write(z +"</br>");
   </script>
   <p>Change the values of the variables and test the resultant values</p>
</body>
</html>
JavaScript Multiplication (*) Operator
The JavaScript multiplication operator multiplies two numbers (operands). It gives the product of two operands. It is denoted by the asterisk (*) symbol. If two operands are of same sign, the product is positive. If the two operands are of different sign, the product is negative.
If any or both operands are string, it converts the string to number and then returns their product.
Example
In the example below, we demonstrate the use of multiplication operator on different types of operands.
<html>
<body>
   <script>
      var x = 20; y = 10;
      var z = x * y ;
      document.write(z +"</br>");
      x = "20"; y = "10"
      z = x * y ;
      document.write(z +"</br>");
      x = "20ee"; 
      z = x * y ;
      document.write(z +"</br>");
   </script>
   <p>Change the values of the variables and test the resultant values</p>
</body>
</html>
JavaScript Division (/) Operator
The JavaScript division (/) operator divides the left operand (dividend) by the right operand (divisor) and returns the quotient. It is represented by the slash (/) symbol.
20/10  // returns 2
20/-10 // return -2
100/0  // returns Infinity
0/0    // returns NaN
Example
Let's demonstrate the use of division operator.
<html>
<body>
   <script>
      var x = 20; y = 10;
      var z = x / y ;
      document.write(z +"</br>");
      x = "20"; y = "10"
      z = x / y ;
      document.write(z +"</br>");
      z = x / 0 ;
      document.write(z +"</br>");
      z = 0 / 0 ;
      document.write(z +"</br>");
   </script>
   <p>Change the values of the variables and test the resultant values</p>
</body>
</html>
JavaScript Modulus (%) Operator
The JavaScript modulus (%) operator returns the remainder when first operand is divided by the second operand. It is also known as remainder operator. It is denoted by the percent (%) symbol. It takes the sign of dividend. Let’s take an example 5%3 gives 2 because when 5 is divided by 3, it gives remainder as 2.
Example
Let's understand the modulus operator with the help of an example program.
<html>
<body>
   <script>
      var x = 20 % 9;
      var y = -20 % 9;
      var z = 20.43 % 9;
      var a = 20 % -9;
      var b = 20 % 10;
      document.write(x +"</br>");
      document.write(y +"</br>");
      document.write(z +"</br>");
      document.write(a +"</br>");
      document.write(b +"</br>");
   </script>
  </body>
</html>
JavaScript Increment (++) Operator
The JavaScript increment (++) operator increases the value of operand by one. It is an unary operator. It takes only one operand. It is denoted by double plus (++) sign.
There are two types of increment operator in JavaScript
Prefix Increment Operator
The prefix increment operator increments the value of the variable before its current value is used. For example,
var x = 10;
var y = ++x; // x is now 11 and y is also 11.
Postfix Increment Operator
The postfix increment operator increments the value of the variable after its current value is used. For example,
var a = 10;
var b = a++; // a is now 11 but b is 10.
Here, in the second line of the above code, first the current value of a is assigned to b, then it is incremented.
Let’s look at the following example −
<html>
<body>
   <script>
      var x = 10;
      var y = --x;  //prefix decrement
      var a = 10;
      var b = a--;  // postfix decrement
	  document.write("x = " + x);
      document.write(" y = " + y + "<br>");
      document.write("a = " + a);
      document.write(" b = " + b + "<br>");
   </script>
   <p>Change the values of the variables and check the results</p>
</body>
</html>
JavaScript Decrement (--) Operator
The JavaScript decrement (--) operator decreases the value of operand by one. It is also an unary operator, i.e., it takes only one operand. It is denoted by double minus (--) sign.
There are two types of decrement operator in JavaScript
Prefix Decrement Operator
The prefix decrement operator decrements the value of the variable before its current value is used. For example,
var x = 10;
var y = --x; // x is now 9 and y is also 9.
Postfix Decrement Operator
The postfix decrement operator decrements the value of the variable after its current value is used. For example,
var a = 10;
var b = a--; // a is now 9 but b is 10.
Here, in the second line of the above code, first the current value of a is assigned to b, then it is decremented.
Let’s look at the following example
﻿
<html>
<body>
   <script>
      var x = 10;
      var y = --x;  //prefix decrement
      var a = 10;
      var b = a--;  // postfix decrement
	  document.write("x = " + x);
      document.write(" y = " + y + "<br>");
      document.write("a = " + a);
      document.write(" b = " + b + "<br>");
   </script>
   <p>Change the values of the variables and check the results</p>
</body>
</html>
﻿
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Operator	Name	Description
`+`	Addition	Adds two operands
`-`	Subtraction	Subtracts the second operand from the first
`*`	Multiplication	Multiply both operands
`/`	Division	Divide the numerator by the denominator
`%`	Modulus	Outputs the remainder of an integer division
`++`	Increment	Increases an integer value by one
`--`	Decrement	Decreases an integer value by one

Javascript Basics

JavaScript Operators

JavaScript Control Flow

JavaScript Functions

JavaScript Objects

Object Oriented JavaScript

JavaScript Versions

JavaScript Cookies

JavaScript Browser BOM

JavaScript Web APIs

JavaScript Events

JavaScript Tutorial

Arithmetic Operators

JavaScript Arithmetic Operators

JavaScript Addition (+) Operator

Example

JavaScript Subtraction (-) Operator

Example

JavaScript Multiplication (*) Operator

Example

JavaScript Division (/) Operator

Example

JavaScript Modulus (%) Operator

Example

JavaScript Increment (++) Operator

Prefix Increment Operator

Postfix Increment Operator

JavaScript Decrement (--) Operator

Prefix Decrement Operator

Postfix Decrement Operator