Comparison & Logical Operators

Learn how to compare values and combine conditions using comparison and logical operators in JavaScript.

What are Comparison Operators?

Comparison operators compare two values and produce a Boolean result: true or false.

They are commonly used when a program needs to make a decision based on two values.

JavaScript comparison and logical operators

JavaScript comparison and logical operator reference.

Comparison Operators

Equal

Checks whether two values are equal after type conversion when necessary.

===

Strict Equal

Checks whether both value and type are equal.

Not Equal

Checks whether two values are not equal.

!==

Strict Not Equal

Checks whether value or type is different.

Greater Than

Checks whether the left value is greater.

Less Than

Checks whether the left value is smaller.

Logical Operators

Logical AND

Returns true when both conditions are true.

Logical OR

Returns true when at least one condition is true.

Logical NOT

Reverses a Boolean result.

How Comparison and Logical Operators Work

Values → Comparison → Conditions → Logical Result

marks >= 40 Condition 1

→

attendance >= 75 Condition 2

→

&& Logical AND

→

true / false Final Result

Example 1: Comparison Operators

Comparison operators can be used to check marks, age, price, quantity, or any other values.

const marks = 78;
const requiredMarks = 40;
const enteredMarks = "78";

console.log("Marks Passed:", marks >= requiredMarks);
console.log("Marks Equal:", marks == enteredMarks);
console.log("Strict Equal:", marks === enteredMarks);
console.log("Marks Greater Than 90:", marks > 90);
console.log("Not Equal to 50:", marks != 50);

Output

Marks Passed: true
Marks Equal: true
Strict Equal: false
Marks Greater Than 90: false
Not Equal to 50: true

Example 2: Logical Operators

Logical operators help us combine multiple conditions into a single expression.

const marks = 82;
const attendance = 88;

const marksPassed = marks >= 40;
const attendancePassed = attendance >= 75;

const eligible = marksPassed && attendancePassed;
const specialCase = marksPassed || attendance > 90;

console.log("Marks Passed:", marksPassed);
console.log("Attendance Passed:", attendancePassed);
console.log("Eligible:", eligible);
console.log("Special Case:", specialCase);
console.log("Not Eligible:", !eligible);

Output

Marks Passed: true
Attendance Passed: true
Eligible: true
Special Case: true
Not Eligible: false

Important Note

== vs ===

== compares values and may perform type conversion.

=== performs a strict comparison, so both value and type must match.

Summary

Comparison operators compare values and return Boolean results. Common comparison operators include ==, ===, !=, !==, > and <. Logical operators such as &&, || and ! are used to combine or reverse conditions.