在此页

• 句法
• 描述
• Polyfill
• 范例
• 规范
• 浏览器兼容性
• 另请参阅
• 相关话题

Math.cbrt() function returns the cube root of a number, that is

$$\mathtt{Math.cbrt(x)} = \sqrt[3]{x} = \text{the unique} \; y \; \text{such that} \; y^3 = x$$

The source for this interactive example is stored in a GitHub repository. If you'd like to contribute to the interactive examples project, please clone https://github.com/mdn/interactive-examples and send us a pull request.

句法

Math.cbrt(x)
					

参数

x

A number.

返回值

The cube root of the given number.

描述

因为 cbrt() is a static method of Math , you always use it as Math.cbrt() , rather than as a method of a Math object you created ( Math is not a constructor).

Polyfill

For all $x \geq 0$ , have $\sqrt[3]{x} = x^{1/3}$ so this can be emulated by the following function:

if (!Math.cbrt) {
  Math.cbrt = (function(pow) {
    return function cbrt(x){
      // ensure negative numbers remain negative:
      return x < 0 ? -pow(-x, 1/3) : pow(x, 1/3);
    };
  })(Math.pow); // localize Math.pow to increase efficiency
}
					

范例

Using Math.cbrt()

Math.cbrt(NaN); // NaN
Math.cbrt(-1); // -1
Math.cbrt(-0); // -0
Math.cbrt(-Infinity); // -Infinity
Math.cbrt(0); // 0
Math.cbrt(1); // 1
Math.cbrt(Infinity); // Infinity
Math.cbrt(null); // 0
Math.cbrt(2);  // 1.2599210498948732
					

规范

规范
ECMAScript (ECMA-262) The definition of 'Math.cbrt' in that specification.

浏览器兼容性

The compatibility table in this page is generated from structured data. If you'd like to contribute to the data, please check out https://github.com/mdn/browser-compat-data

相关话题

1. 标准内置对象
2. Math
3. 特性
   1. Math.E
   2. Math.LN10
   3. Math.LN2
   4. Math.LOG10E
   5. Math.LOG2E
   6. Math.PI
   7. Math.SQRT1_2
   8. Math.SQRT2
4. 方法
   1. Math.abs()
   2. Math.acos()
   3. Math.acosh()
   4. Math.asin()
   5. Math.asinh()
   6. Math.atan()
   7. Math.atan2()
   8. Math.atanh()
   9. Math.cbrt()
   10. Math.ceil()
   11. Math.clz32()
   12. Math.cos()
   13. Math.cosh()
   14. Math.exp()
   15. Math.expm1()
   16. Math.floor()
   17. Math.fround()
   18. Math.hypot()
   19. Math.imul()
   20. Math.log()
   21. Math.log10()
   22. Math.log1p()
   23. Math.log2()
   24. Math.max()
   25. Math.min()
   26. Math.pow()
   27. Math.random()
   28. Math.round()
   29. Math.sign()
   30. Math.sin()
   31. Math.sinh()
   32. Math.sqrt()
   33. Math.tan()
   34. Math.tanh()
   35. Math.trunc()
5. 继承：
6. Object
7. 特性
   1. Object.prototype.__proto__
   2. Object.prototype.constructor
8. 方法
   1. Object.prototype.__defineGetter__()
   2. Object.prototype.__defineSetter__()
   3. Object.prototype.__lookupGetter__()
   4. Object.prototype.__lookupSetter__()
   5. Object.prototype.hasOwnProperty()
   6. Object.prototype.isPrototypeOf()
   7. Object.prototype.propertyIsEnumerable()
   8. Object.prototype.toLocaleString()
   9. Object.prototype.toSource()
   10. Object.prototype.toString()
   11. Object.prototype.valueOf()
   12. Object.setPrototypeOf()