function createPassword(min,max) {
 //可以生成随机密码的相关数组
 var num = ["0","1","2","3","4","5","6","7","8","9"];
 var english = ["a","b","c","d","e","f","g","h","i","j","k","l","m","n","o","p","q","r","s","t","u","v","w","x","y","z"];
 var ENGLISH = ["A","B","C","D","E","F","G","H","I","J","K","L","M","N","O","P","Q","R","S","T","U","V","W","X","Y","Z"];
 var special = ["-","_","#"];
 var config = num.concat(english).concat(ENGLISH).concat(special);

 //先放入一个必须存在的
 var arr = [];
 arr.push(getOne(num));
 arr.push(getOne(english));
 arr.push(getOne(ENGLISH));
 arr.push(getOne(special));

 //获取需要生成的长度
 var len = min + Math.floor(Math.random()*(max-min+1));

 for(var i=4; i<len; i++){
  //从数组里面抽出一个
  arr.push(config[Math.floor(Math.random()*config.length)]);
 }

 //乱序
 var newArr = [];
 for(var j=0; j<len; j++){
  newArr.push(arr.splice(Math.random()*arr.length,1)[0]);
 }

 //随机从数组中抽出一个数值
 function getOne(arr) {
  return arr[Math.floor(Math.random()*arr.length)];
 }

 return newArr.join("");
 }

console.log(createPassword(8,15));