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Math.PI

概述

Math.PI 表示一个圆的周长与直径的比例,约为 3.14159:

Math.PI=π3.14159\mathtt{\mi{Math.PI}} = \pi \approx 3.14159

Math.PI 属性的属性特性:
writable false
enumerable false
configurable false

描述

由于 PIMath 的静态属性,所以应该像这样使用:Math.PI,而不是作为你创建的 Math 实例的属性(Math 不是构造函数)。

示例

使用 Math.PI

下面的函数使用 Math.PI 计算给定半径的圆周长:

function calculateCircumference (radius) {
  return 2 * Math.PI * radius;
}

calculateCircumference(1);  // 6.283185307179586

规范

规范版本 规范状态 注解
ECMAScript 1st Edition. Implemented in JavaScript 1.0 Standard Initial definition.
ECMAScript 5.1 (ECMA-262)
Math.PI
Standard  
ECMAScript 2015 (6th Edition, ECMA-262)
Math.PI
Standard  

浏览器兼容性

Feature Chrome Firefox (Gecko) Internet Explorer Opera Safari
Basic support (Yes) (Yes) (Yes) (Yes) (Yes)
Feature Android Chrome for Android Firefox Mobile (Gecko) IE Mobile Opera Mobile Safari Mobile
Basic support (Yes) (Yes) (Yes) (Yes) (Yes) (Yes)

相关链接

  • The Math object it belongs to.

文档标签和贡献者

 此页面的贡献者: helloguangxue, yenshen, AlexChao
 最后编辑者: helloguangxue,