JavaScript - Operators

An operator is used for getting some process between operands.


JavaScript supports lots type of Operators We not going deeply on all operators but lets go through all type.

Arithmetic Operators

Operator Description Example Result
+ Addition

x=2

y=2

x+y

4
- Substraction

x=5

y=2

x-y

3
* Multiplication

x=5

y=4

x*y

20
/ Division

x=15

y=5

x/y

3
% Modulus (division remainder)

x = 5

y = 2

x/y

1
++ Increment

x=5

x++

6
-- Decrement

x = 5

x--

4

 

Example:

<script language="JavaScript">

var a = 5;

++a;

alert("The value of a = " + a );

</script>

Assignment Operators

Operator Description Example
= Equal Assign

x = y

x = 10

+= Addition & Equal

x += y

x = x + y

-= Substraction & Equal

x -= y

x = x - y

*= Multiplication & Equal

x * = y

x = x * y

/= Division & Equal

x /= y

x = x / y

%= Modulation & Equal

x % y

x = x % y

     


Example:

<script language="JavaScript">

var a = 10;

var b = 2;

a+=b;

alert("The value of a +=b is = " + a );

</script>

 
Comparison  Operators

Operators Description Example Result
== Is equal to 5 == 8 false
=== Is equal to (check for both value & type)

x = 5

y=*5*

x==y

x===y

 

 

true

false

!= Is not equal 5!=8 false
> Is greater than 5>8 false
< Is less than 5<8 true
>= Is greater than or equal to 5>=8 false
<= Is less than or equal to 5<=8 false


Example:

<script language="JavaScript">
var a = 5;
var b = 6;
a= a>b;
alert("The value of a = " + a );
</script>
 
Logical  Operators

Operator Description Example Result
&& And

x=6

y=3

(x<10 && y>1)

 

 

true

|| Or

x=6

y=3

(x == 5 || y == 5)

false
! Not

x=6

y=3

!(x == y)

 

 

false

 

Example:
<script language="JavaScript">

var userID;
var password;
userID = prompt("Enter User ID " , " ");

password = prompt ("Enter Password"," ");

if (userID == "Visions" && password == "Developer")
{
Alert ("Valid Login");
}
else
{
Alert(“Invalid Login”);
}

</script>


String  Operator
A string is most often text, for example “Hello Good Morning”. To Stick or join two or more string variables together use the + operator (String Operator).
Example :
                    Txt1 = "Visions"
                    Txt2 = "Developer"
                    Txt3 = Txt1 + " " + Txt2

Now the Txt3 Variable Contain Visions Developer

Conditional Operator
JavaScript is scripting language but still it contains a conditional operator that assign a value to a variable based on some condition.
                Syntax :  varname = (condition)?value1:value2
               

Example: Msg = (userId = "CEO")?"Welcome ABC":"Welcome"

If the variable userId is equal to "CEO", then put the string "Welcome ABC" in the variable named Msg. If the variable userID is not equal to "CEO", the put the string "Welcome" into the variable named greeting.