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JavaScript Operators

Arithmetic Operators

Operator Description Example Result
+ Addition 2+2 4
- Subtraction 5-2 3
* Multiplication 4*5 20
/ Division 15/5
5/2
3
2.5
% Modulus. Returns the remainder after the first division

Example 1:
5/2 results in 2, remainder 1
Example 2:
10/8 results in 1, remainder 2

5%2
10%8
1
2
++ Increment x=5
x++
x=6
-- Decrement x=5
x--
x=4


Comparison Operators

Operator Description Example
== is equal to 5==8 returns false
!= is not equal 5!=8 returns true
> is greater than 5>8 returns false
< is less than 5<8 returns true
>= is greater than or equal to 5>=8 returns false
<= is less than or equal to 5<=8 returns true


Assignment Shorthand Operators

Operator Example Is The Same As
+= x+=y x=x+y
-= x-=y x=x-y
*= x*=y x=x*y
/= x/=y x=x/y
%= x%=y x=x%y


Logical Operators

Operator Description Example
&& and x=6
y=3

(x < 10 && y > 1) returns true

|| or x=6
y=3

(x==5 || y==5) returns false

! not x=6
y=3

x != y returns true



String Operator

A string is most often a text, for example "Hello World!". To stick two or more string variables together, use the + operator.

txt1="What a very"
txt2="nice day!"
txt3=txt1+txt2 

The variable txt3 now contains "What a verynice day!".

To add a space between two string variables, insert a space into the expression, OR in one of the strings.

txt1="What a very"
txt2="nice day!"
txt3=txt1+" "+txt2
or
txt1="What a very "
txt2="nice day!"
txt3=txt1+txt2

The variable txt3 now contains "What a very nice day!".