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    Math.sign()

    This is an experimental technology, part of the ECMAScript 6 (Harmony) 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 x 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

    Math.sign = Math.sign || function(x) {
      x = +x; // convert to a number
      if (x === 0 || isNaN(x)) {
        return x;
      }
      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 38 25 (25) Not supported 25 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

    Document Tags and Contributors

    Last updated by: Mingun,