This is an experimental technology, part of the Harmony (ECMAScript 6) proposal.
Because this technology's specification has not stabilized, check the compatibility table for usage in various browsers. Also note that the syntax and behavior of an experimental technology is subject to change in future version of browsers as the spec changes.
Summary
The Math.sign() function returns the sign of a number, indicating whether the number is positive, negative or zero.
Syntax
Math.sign(x)Parameters
-
x - A number.
Description
Because sign is a static method of Math, you always use it as Math.sign(), rather than as a method of a Math object you created (Math is not a constructor).
This function has 5 kinds of return values, 1, -1, 0, -0, NaN, which represent "positive number", "negative number", "positive zero", "negative zero" and NaN respectively.
The argument passed to this function will be converted to number type implicitly.
Examples
Example: Using Math.sign
Math.sign(3) // 1
Math.sign(-3) // -1
Math.sign("-3") // -1
Math.sign(0) // 0
Math.sign(-0) // -0
Math.sign(NaN) // NaN
Math.sign("foo") // NaN
Math.sign() // NaN
Polyfill
function sign(x) {
if(isNaN(x)) {
return NaN;
} else if(x === 0) {
return x;
} else {
return (x > 0 ? 1 : -1);
}
}
Specifications
| Specification | Status | Comment |
|---|---|---|
| ECMAScript 6 (ECMA-262) The definition of 'Math.sign' in that specification. |
Draft | Initial definition. |
Browser compatibility
| Feature | Chrome | Firefox (Gecko) | Internet Explorer | Opera | Safari |
|---|---|---|---|---|---|
| Basic support | Not supported | 25 (25) | Not supported | Not supported | Not supported |
| Feature | Android | Chrome for Android | Firefox Mobile (Gecko) | IE Mobile | Opera Mobile | Safari Mobile |
|---|---|---|---|---|---|---|
| Basic support | Not supported | Not supported | 25.0 (25) | Not supported | Not supported | Not supported |
See also
- The
Mathobject it belongs to.