Inequality (!=)

The inequality operator (!=) checks whether its two operands are not equal, returning a Boolean result. Unlike the strict inequality operator, it attempts to convert and compare operands that are of different types.


x != y


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:

x != y

!(x == y)

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:

3 != "3"; // false

To prevent this, and require that different types are considered to be different, use the strict inequality operator instead:

3 !== "3"; // true


Comparison with no type conversion

1 != 2;              // true
"hello" != "hola";   // true

1 != 1;              // false
"hello" != "hello";  // false

Comparison with type conversion

"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

const object1 = {"key": "value"}
const object2 = {"key": "value"};

object1 != object2 // true
object2 != object2 // false


ECMAScript (ECMA-262)
The definition of 'Equality operators' in that specification.

Browser compatibility

ChromeEdgeFirefoxInternet ExplorerOperaSafariAndroid webviewChrome for AndroidFirefox for AndroidOpera for AndroidSafari on iOSSamsung InternetNode.js
Inequality (a != b)Chrome Full support 1Edge Full support 12Firefox Full support 1IE Full support 3Opera Full support 3Safari Full support 1WebView Android Full support 1Chrome Android Full support 18Firefox Android Full support 4Opera Android Full support 10.1Safari iOS Full support 1Samsung Internet Android Full support 1.0nodejs Full support 0.1.100


Full support
Full support

See also