How to Use Comparison Operators in JavaScript: Syntax and Examples

In JavaScript, use ==, ===, !=, !==, <, <=, >, and >= to compare values. The === and !== operators check both value and type, while == and != compare values with type conversion.

Syntax

Comparison operators compare two values and return true or false. Here are the main operators:

• ==: Equal to (compares values with type conversion)
• ===: Strict equal to (compares value and type)
• !=: Not equal to (compares values with type conversion)
• !==: Strict not equal to (compares value and type)
• <: Less than
• <=: Less than or equal to
• >: Greater than
• >=: Greater than or equal to

javascript

value1 == value2
value1 === value2
value1 != value2
value1 !== value2
value1 < value2
value1 <= value2
value1 > value2
value1 >= value2

Example

This example shows how to use different comparison operators and their results.

javascript

const a = 5;
const b = '5';

console.log(a == b);   // true because values are equal after type conversion
console.log(a === b);  // false because types differ (number vs string)
console.log(a != b);   // false because values are equal after type conversion
console.log(a !== b);  // true because types differ
console.log(a < 10);   // true
console.log(a >= 5);   // true
console.log(a > 10);   // false

Output

true
false
false
true
true
true
false

Common Pitfalls

Using == and != can cause unexpected results because they convert types before comparing. Always prefer === and !== to avoid bugs.

Also, be careful when comparing null or undefined with == as it can be confusing.

javascript

const x = 0;
const y = false;

// Wrong: uses == which converts types
console.log(x == y);  // true (unexpected for some)

// Right: uses === which checks type and value
console.log(x === y); // false

Output

true
false

Quick Reference

Operator	Meaning	Example	Result
==	Equal (with type conversion)	5 == '5'	true
===	Strict equal (no type conversion)	5 === '5'	false
!=	Not equal (with type conversion)	5 != '6'	true
!==	Strict not equal (no type conversion)	5 !== '5'	true
<	Less than	3 < 5	true
<=	Less than or equal	5 <= 5	true
>	Greater than	7 > 10	false
>=	Greater than or equal	7 >= 7	true

Key Takeaways

Use === and !== to compare both value and type safely.

Avoid == and != to prevent unexpected type coercion.

Comparison operators return true or false based on the comparison.

Use <, <=, >, >= to compare numeric or string values.

Be cautious when comparing null or undefined with ==.