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# JavaScript Operators

In this tutorial you will learn how to manipulate or perform the operations on variables and values using the operators in JavaScript.

## What are Operators in JavaScript

Operators are symbols or keywords that tell the JavaScript engine to perform some sort of actions. For example, the addition (`+`) symbol is an operator that tells JavaScript engine to add two variables or values, while the equal-to (`==`), greater-than (`>`) or less-than (`<`) symbols are the operators that tells JavaScript engine to compare two variables or values, and so on.

The following sections describe the different operators used in JavaScript.

## JavaScript Arithmetic Operators

The arithmetic operators are used to perform common arithmetical operations, such as addition, subtraction, multiplication etc. Here's a complete list of JavaScript's arithmetic operators:

Operator Description Example Result
`+` Addition `\$x + \$y` Sum of \$x and \$y
`-` Subtraction `\$x - \$y` Difference of \$x and \$y.
`*` Multiplication `\$x * \$y` Product of \$x and \$y.
`/` Division `\$x / \$y` Quotient of \$x and \$y
`%` Modulus `\$x % \$y` Remainder of \$x divided by \$y

The following example will show you these arithmetic operators in action:

#### Example

Try this code »
``````var x = 10;
var y = 4;
alert(x + y); // 0utputs: 14
alert(x - y); // 0utputs: 6
alert(x * y); // 0utputs: 40
alert(x / y); // 0utputs: 2.5
alert(x % y); // 0utputs: 2``````

## JavaScript Assignment Operators

The assignment operators are used to assign values to variables.

Operator Description Example Is The Same As
`=` Assign `x = y` `x = y`
`+=` Add and assign `x += \$` `x = x + y`
`-=` Subtract and assign `x -= y` `x = x - y`
`*=` Multiply and assign `x *= y` `x = x * y`
`/=` Divide and assign quotient `x /= y` `x = x / y`
`%=` Divide and assign modulus `x %= y` `x = x % y`

The following example will show you these assignment operators in action:

#### Example

Try this code »
``````var x;    // Declaring Variable

x = 10;

x = 20;
x += 30;

x = 50;
x -= 20;

x = 5;
x *= 25;

x = 50;
x /= 10;

x = 100;
x %= 15;

## JavaScript String Operators

There are two operators which can also used be for strings.

Operator Description Example Result
`+` Concatenation `str1 + str2` Concatenation of str1 and str2
`+=` Concatenation assignment `str1 += str2` Appends the str2 to the str1

The following example will show you these string operators in action:

#### Example

Try this code »
``````var str1 = "Hello";
var str2 = " World!";

alert(str1 + str2); // Outputs: Hello World!

str1 += str2;

## JavaScript Incrementing and Decrementing Operators

The increment/decrement operators are used to increment/decrement a variable's value.

Operator Name Effect
`++x` Pre-increment Increments x by one, then returns x
`x++` Post-increment Returns x, then increments x by one
`--x` Pre-decrement Decrements x by one, then returns x
`x--` Post-decrement Returns x, then decrements x by one

The following example will show you how increment and decrement operators actually work:

#### Example

Try this code »
``````var x; // Declaring Variable

x = 10;

x = 10;

x = 10;

x = 10;

## JavaScript Logical Operators

The logical operators are typically used to combine conditional statements.

Operator Name Example Result
`&&` And `x && y` True if both x and y are true
`||` Or `x || y` True if either x or y is true
`!` Not `!x` True if x is not true

The following example will show you how these logical operators actually work:

#### Example

Try this code »
``````var year = 2018;

// Leap years are divisible by 400 or by 4 but not 100
if((year % 400 == 0) || ((year % 100 != 0) && (year % 4 == 0))){
alert(year + " is a leap year.");
} else{
alert(year + " is not a leap year.");
}``````

You will learn about conditional statements in JavaScript if/else chapter.

## JavaScript Comparison Operators

The comparison operators are used to compare two values in a Boolean fashion.

Operator Name Example Result
`==` Equal `x == y` True if x is equal to y
`===` Identical `x === y` True if x is equal to y, and they are of the same type
`!=` Not equal `x != y` True if x is not equal to y
`!==` Not identical `x !== y` True if x is not equal to y, or they are not of the same type
`<` Less than `x < y` True if x is less than y
`>` Greater than `x > y` True if x is greater than y
`>=` Greater than or equal to `x >= y` True if x is greater than or equal to y
`<=` Less than or equal to `x <= y` True if x is less than or equal to y

The following example will show you these comparison operators in action:

#### Example

Try this code »
``````var x = 25;
var y = 35;
var z = "25";

alert(x == z);  // Outputs: true
alert(x === z); // Outputs: false
alert(x != y);  // Outputs: true
alert(x !== z); // Outputs: true
alert(x < y);   // Outputs: true
alert(x > y);   // Outputs: false
alert(x <= y);  // Outputs: true
alert(x >= y);  // Outputs: false``````