四时宝库

var rand_pool = ["a","b","c","d","e","f","g","h","i","j","k","m","n","p","q","r","s","t","u","v","w","x","y","z","1","2","3","4","5","6","7","8","9"];
var rand_word = function(){ return rand_pool[parseInt( rand_pool.length * Math.random() )]};
var rand_four = rand_word() + rand_word() + rand_word() + rand_word();

console.log(rand_four);

三行代码，产生一个随机字符串

代码说明：

1、先建立一个随机数池，

2、再定义一个随数机数产生函数，重点是：rand_pool[parseInt( rand_pool.length * Math.random() )],Math.random()产生一个不包含1的0-1之间的随机数，用rand_pool.length相乘，得到0到rand_pool.length之间的值，由于此值含小数点，因此再用parseInt转为整数，再用它做为rand_pool的下标，即可得到一个rand_pool中的随机内容。

3、最后，要获取几位的随机内容，就调用几次rand_word，当然的，也可以用循环。