Page 90 - DCAP202_Fundamentals of Web Programming

Unit 7: Operators in JavaScript

var d = c; Notes
c += 1; // c = 2, d = 1;

7.1.5 Comparison Operators

There are following comparison operators supported by JavaScript language
Assume variable A holds 10 and variable B holds 20 then, see Table 7.4:

Table 7.4: Comparison Operators

Operator Description Example
Checks if the value of two operands are equal or not, (A == B) is not
==
if yes then condition becomes true. true.
Checks if the value of two operands are equal or not,
!= (A != B) is true.
if values are not equal then condition becomes true.
Checks if the value of left operand is greater than
> the value of right operand, if yes then condition (A > B) is not true.
becomes true.
Checks if the value of left operand is less than the
< value of right operand, if yes then condition (A < B) is true.
becomes true.
Checks if the value of left operand is greater than or
(A >= B) is not
>= equal to the value of right operand, if yes then
true.
condition becomes true.
Checks if the value of left operand is less than or
<= equal to the value of right operand, if yes then (A <= B) is true.
condition becomes true.

7.1.6 Logical Operators

Operator Description
&& and
|| or
! not

7.1.7 Other Operators

The Conditional Operator (? :)

There is an operator called conditional operator. This first evaluates an expression for a true or
false value and then execute one of the two given statements depending upon the result of the
evaluation. The conditional operator has this syntax:

Operator Description Example
If Condition is true ? Then value X :
? : Conditional Expression
Otherwise value Y

The typeof Operator

The typeof is a unary operator that is placed before its single operand, which can be of any type.

LOVELY PROFESSIONAL UNIVERSITY 83