js random函数以一定概率生成一段数字范围的方法
如实现下列概率数字需求
40% to get number from 1-10
20% to get number from 11-20
30% to get number from 21-30
10% to get number from 31-35
参考的代码,以一定概率取值
function test(){
var rnd = Math.random(),
rnd2 = Math.random();
if(rnd<0.4) return (1 + Math.floor(1000 * rnd2)/100);
else if(rnd<0.6) return (11 + Math.floor(1000 * rnd2)/100);
else if(rnd<0.9) return (21 + Math.floor(1000 * rnd2)/100);
else return (31 + Math.floor(500 * rnd2)/100);
}