## JavaScript Operators

Operators are symbols or keywords that instruct the JavaScript engines to take certain actions. The addition (+) sign, for example, instructs the JavaScript engine will add two variables or variables, whereas the equal-to (==), greater-than (>), or less-than () symbols instruct the JavaScript engine to compare two variables or values, and so on.

The sections that follow discuss the various JavaScript operators.

### JavaScript Arithmetic Operators

The arithmetic operators is used to accomplish basic arithmetic operations including addition, subtraction, multiplication, and so on. The following is an exhaustive 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

Example

```< !DOCTYPE html>
< html lang="en">
< meta charset="utf-8">
< title>JavaScript Arithmetic Operators< /title>
< body>
< script>
var a = 20;
var b = 5;
document.write(a + b);
document.write("< br>");

document.write(a - b);
document.write("< br>");

document.write(a * b);
document.write("< br>");

document.write(a / b);
document.write("< br>");

document.write(a % b);
< /script>
< /body>
< /html>
```

Output

```25
15
100
4
0
```

### JavaScript Assignment Operators

Variables are assigned values using assignment operators.

Operator Description Example Is The Same As
= Assign x = y x = y
+= Add and assign x += y 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

Example

```< !DOCTYPE html>
< html lang="en">
< meta charset="utf-8">
< title>JavaScript Assignment Operators< /title>
< body>
< script>
var a;    // Declaring Variable

a = 50;
document.write(a + "< br>");

a = 50;
a += 20;
document.write(a + "< br>");

a = 50;
a -= 30;
document.write(a + "< br>");

a = 50;
a *= 3;
document.write(a + "< br>");

a = 50;
a /= 10;
document.write(a + "< br>");

a = 50;
a %= 5;
document.write(a);
< /script>
< /body>
< /html>
```

Output

```50
70
20
150
5
0
```

### JavaScript String Operators

There are two operations that may also be was using on strings.

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

Example

```< !DOCTYPE html>
< html lang="en">
< meta charset="utf-8">
< title>JavaScript String Operators< /title>
< body>
< script>
var str1 = "Hello";
var str2 = " Friends!";

document.write(str1 + str2 + "< br>");

str1 += str2;
document.write(str1);
< /script>
< /body>
< /html>
```

Output

```Hello Friends!
Hello Friends!
```

### JavaScript Incrementing and Decrementing Operators

The increment/decrement expressions are utilized to increase or decrease the value for a variable.

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

Example

```< !DOCTYPE html>
< html lang="en">
< meta charset="utf-8">
< title>JavaScript Incrementing and Decrementing Operators< /title>
< body>
< script>
var x; // Declaring Variable

a = 100;
document.write(++a);
document.write("< p>" + a + "< /p>");

a = 100;
document.write(a++);
document.write("< p>" + a + "< /p>");

a = 100;
document.write(--a);
document.write("< p>" + a + "< /p>");

x = 100;
document.write(a--);
document.write("< p>" + a + "< /p>");
< /script>
< /body>
< /html>
```

Output

```101
101
100
101
99
99
99
98
```

### JavaScript Logical Operators

Conditional expressions is commonly combined using logical operators.

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

Example

```< !DOCTYPE html>
< html lang="en">
< meta charset="utf-8">
< title>JavaScript Logical Operators< /title>
< body>
< script>
var year = 2021;

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

Output

2021 is not a leap year.

### JavaScript Comparison Operators

The comparison operations are used to do a Boolean comparison between two variables.

Operator Name Example Result
== Equal x == y True if x is equal to y, and they are of the same type
=== 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

Example

```< !DOCTYPE html>
< html lang="en">

< title>JavaScript Comparison Operators< /title>
< body>
< script>
var a = 50;
var b = 80;
var c = "50";

document.write(a == c);
document.write("< br>");

document.write(a === c);
document.write("< br>");

document.write(a != b);
document.write("< br>");

document.write(a !== c);
document.write("< br>");

document.write(a < b);
document.write("< br>");

document.write(a > b);
document.write("< br>");

document.write(a <= b);
document.write("< br>");

document.write(a >= b);
< /script>
< /body>
< /html>
```

Output

```true
false
true
true
true
false
true
false
```