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.


The Math.sign() function returns the sign of a number, indicating whether the number is positive, negative or zero.




A number.


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.


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


Specification Status Comment
ECMAScript Language Specification 6th Edition (ECMA-262) Draft Initial definition.

Browser compatibility

Feature Chrome Firefox (Gecko) Internet Explorer Opera Safari
Basic support 32 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 Math object it belongs to.

Document Tags and Contributors

Contributors to this page: ziyunfei, fscholz
Last updated by: ziyunfei,