When should you use === vs ==, !== vs !=, etc.. in javascript?

javascript equals literals
Matt picture Matt · Jul 7, 2009 · Viewed 10.9k times · Source

Possible Duplicate:
Javascript === vs == : Does it matter which “equal” operator I use?

What are the differences between === vs == and !== vs !=?

When should you use each one?

Answer

Matthew Vines picture Matthew Vines · Jul 7, 2009

=== is the Identity operator, and is used to test that value and type are equal.

so..

"3" == 3 // true
"3" === 3 // false
1 == true // true
1 === true // false
"1" == true // true
"1" === true // false

so when you care that value and type are equal, or not equal use Identity operators === or !==

Related questions

How to determine equality for two JavaScript objects?

A strict equality operator will tell you if two object types are equal. However, is there a way to tell if two objects are equal, much like the hash code value in Java? Stack Overflow question Is there any kind …

Read More
How do I test if a variable does not equal either of two values?

I want to write an if/else statement that tests if the value of a text input does NOT equal either one of two different values. Like this (excuse my pseudo-English code): var test = $("#test").val(); if (test does not …

Read More
Why does "true" == true show false in JavaScript?

MDC describes the == operator as follows: If the two operands are not of the same type, JavaScript converts the operands then applies strict comparison. If either operand is a number or a boolean, the operands are converted to numbers if …

Read More