JavaScript Variables Tutorials - Variables and Operators

Full Tutorial List           Tutorials (50)       Sept 01, 2009

ASSIGNING VALUES TO VARIABLES:


An operator acts upon a variable and changes its value. Some sample operators are



 
+ Addition/String addition 
- Subtraction 
* Multiplication 
/ Division 
% Modulus

Most operators are mathematical, i.e. they only work on number variables, Basically ther are 4 different kinds of operators: arithmetic, relational, boolean, and bitwise operators. For now, we will skip the bitwise operators.

Examples of Arithmetic Operators



 
Example 		Result

a=5; 		a now equals 5.
a=5; a++	a now increments by 1 and becomes 6.
a=5; a--	a now decrements by 1 and becomes 4.
myName="Fergal";	String myName now contains Fergal.
a=2*3;		a now contains the value 6.
a=5-2;		a now contains the value 3.
a=5+2;		a now equals 7.

their are plenty of other operators that you can use, you can lists of these on the internet.

Relational Operators Operator Meaning 



 
== equivalent to 
!= not equal to 
> greater than 
< less than 
>= greater than or equal to 
<= less than or equal to

Example Boolean Operators:



 
&& - Returns true if both expressions are true. 
|| - Returns true if one expression is true. 
! - Used with only one expression. 
Returns true if expression is false, false if the expression is true

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