JavaScript Comparison and Logical Operators Explained

JAVASCRIPT
COMPARISON AND
LOGICAL OPERATORS
BENJAMIN B. ESGUERRA MEMORIAL NATIONAL HIGH
SCHOOL

JavaScript Comparison and Logical
Operators

 Comparison and Logical operators are
used to test for true or false.
 Comparison Operators are used in
logical statements to determine equality
or difference between variables or values.
 Logical Operators are used to determine
the logic between variables or values.

COMPARISON OPERATORS
Given that x=5, the table below explains the comparison operators.

Operator Description Comparing Returns
x==8 FALSE
== is equal to x==5 TRUE
x==="5" FALSE
is exactly equal to (value and type) x===5 TRUE
!= is not equal x!=8 TRUE
x!=="5" TRUE
!== is not equal (neither value or type) x!==5 FALSE
> is greater than x>8 FALSE
< is less than x<8 TRUE
>= is greater than or equal to x>=8 FALSE
<= is less than or equal to x<=8 TRUE

EXAMPLE
<html>
<body>
<script>
var x= 10
var y= 2
var z= (x>y);
confirm("Is "+x+" greater
than "+y+" ?");
alert(""+z+"");
</script>
</body>
</html>

EXAMPLE
<html>
<body>
<script>
var x= parseFloat(prompt(“Enter
the first value”,””));
var y= parseFloat(prompt(“Enter
the second value”,””));
confirm(“Is”+x+”
var z= (x>y);
alert(""+z+"");
</script>
</body>
</html>

LOGICAL OPERATORS
Given that x=6 and y=3 the table below explains the logical
operators.

Operator Description Comparing Returns
&&
(ampersand) and (x<10 && y>1) TRUE

|| or (x==5||y==5) FALSE

! not !(x==y) TRUE

CONDITIONAL OPERATOR
JavaScript also contains a conditional operator that assigns a
value to a variable based on some conditions.

SYNTAX:

variable name= (condition)? value1:value2

Example:
If the variable age is value below 18, the value of the
variable voteable will be “Too young, otherwise the
value of votaable will be “Old enough”

var age= 18
var voteable= (age<18)? “Too young”:”Old
enough”

<html>
<body>
<script>
var x= prompt("Who created the JavaScript? "," ");
var y= “Brendan Eich"
var z= (x==y)?"Correct": "Wrong";
alert(""+z+"");
document.write("Correct Answer: "+y+"");
</script>
</body>
</html>

Assign/Seatwork
Create the JavaScript source code

COMPARISON
50 is less than 68

LOGICAL
50 is equal to 68 and 68 is equal to 50

CONDITIONAL
What is the first calculating device? Abacus
or Comptometer?
Condition: Congratulation! And Try Again

JavaScript Comparison and Logical Operators Explained

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