Course Contents

Javascript Operators

Javascript 2672 Views

Operators are used to perform operations on variables and values. Operators can be divided into the following groups.

Assignment operators

Assignment operators are used to define a value to a variable. The basic assignment operator in javascript is "=". It means that the left operand gets set to the value of the assignment expression on the right.

Assignment Same as... Description
x = y x = y The left operand gets set to the value of the expression on the right
x += y x = x + y Addition
x -= y x = x - y Subtraction
x *= y x = x * y Multiplication
x /= y x = x / y Division
x %= y x = x % y Modulus

Use of Assignment Operators

<script>
x = webtricks;
y = home;
document.write(x);
</script>

Result: 21

Arithmetic operators

The arithmetic operators are used to perform arithmetical operations on data such as addition, substraction, multiplication, etc.

Operator Name 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
** Exponentiation x ** y Result of raising x to the power of y

Use of Arithmetic Operators

<script>
x = 2;
y = 8;
document.write(x**y);
</script>

Result: 256

Comparison operators

Comparison operators are useful when you need to compare two values. It returns boolean value true or false.

Operator Name Example Result
== Equal x == y Returns true if x is equal to y
=== Identical x === y Returns true if x is equal to y, and both of them are string or numeric value
!= Not equal x != y Returns true if x is not equal to y
!== Not identical x !== y Returns true if x is not equal to y, or they are not of the same type
> Greater than x > y Returns true if x is greater than y
< Less than x < y Returns true if x is less than y
>= Greater than or equal to x >= y Returns true if x is greater than or equal to y
<= Less than or equal to x <= y Returns true if x is less than or equal to y

Use of Comparison Operators

<script>
x = 3;
y = 3;
if(x > y){
  document.write('x is greater');
}else if(x < y){
  document.write('y is greater');
}else{
  document.write('Both are equal');
}
</script>

Increment/Decrement operators

The increment operators are used to increase a variable's value by 1 while the decrement operators are used to decrease a variable's value by 1.

Operator Name Description
++x Pre-increment Increases the value of x by 1 and returns x
x++ Post-increment Returns x then increases the value of x by 1
--x Pre-decrement Decreases the value of x by 1, then returns x
x-- Post-decrement Returns x, then decreases the value of x by 1

Use of arithmetic operators

<script>
x = 2;
document.write(x++);
document.write(x);
</script>

The first script will print the value of x as 2 and then increases its value. The second variable x receives the increased value so prints it as 3.

Logical operators

The logical operators are 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

Use of Logical Operators

<script>
x = 2;
y = 3;
if(x > 2 && y > 2){
  document.write("Both are greater than 2");
}else{
  document.write("Either one or both are not greater than 2");
}
</script>
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