概述
Math.random()
函数返回 [0-1) 的浮点值伪随机数(大于等于0,小于1)。
此函数的随机数生成器和java一样以当前时间为随机数种子。
语法
Math.random()
参数
无
示例
例子: 使用 Math.random
Note that as numbers in JavaScript are IEEE 754 floating point numbers with round-to-nearest-even behavior, these ranges, excluding the one for Math.random()
itself, aren't exact, and depending on the bounds it's possible in extremely rare cases (on the order of 1 in 262) to calculate the usually-excluded upper bound.
// 返回一个大于等于0,小于1的伪随机数 function getRandom() { return Math.random(); }
// 返回一个介于min和max之间的随机数 function getRandomArbitrary(min, max) { return Math.random() * (max - min) + min; }
// 返回一个介于min和max之间的整型随机数 // Using Math.round() will give you a non-uniform distribution! function getRandomInt(min, max) { return Math.floor(Math.random() * (max - min + 1) + min); }
规范
规范版本 | 规范状态 | 注解 |
---|---|---|
ECMAScript 1st Edition. JavaScript 1.0 (UNIX Only) / JavaScript 1.1 (All platform) | Standard | Initial definition. |
ECMAScript 5.1 (ECMA-262) Math.random |
Standard | |
ECMAScript 2015 (6th Edition, ECMA-262) Math.random |
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) |