Inequality (!=) - JavaScript | MDN
Try it
console.log(1 != 1);
// Expected output: false
console.log("hello" != "hello");
// Expected output: false
console.log("1" != 1);
// Expected output: false
console.log(0 != false);
// Expected output: false
Syntax
Description
The inequality operator checks whether its operands are not equal. It is the negation of the equality operator so the following two lines will always give the same result:
For details of the comparison algorithm, see the page for the equality operator.
Like the equality operator, the inequality operator will attempt to convert and compare operands of different types:
To prevent this, and require that different types are considered to be different, use the strict inequality operator instead:
Examples
Comparison with no type conversion
js
1 != 2; // true
"hello" != "hola"; // true
1 != 1; // false
"hello" != "hello"; // false
Comparison with type conversion
js
"1" != 1; // false
1 != "1"; // false
0 != false; // false
0 != null; // true
0 != undefined; // true
0 != !!null; // false, look at Logical NOT operator
0 != !!undefined; // false, look at Logical NOT operator
null != undefined; // false
const number1 = new Number(3);
const number2 = new Number(3);
number1 != 3; // false
number1 != number2; // true
Comparison of objects
js
const object1 = {
key: "value",
};
const object2 = {
key: "value",
};
console.log(object1 != object2); // true
console.log(object1 != object1); // false
Specifications
| Specification |
|---|
| ECMAScript® 2027 Language Specification # sec-equality-operators |