判断数组中每个元素出现的次数

   // 判断数组中每个元素出现的次数
   function getEleTimes(arr) {
      var map = {}
      for (i = 0; i < arr.length; i++) {
        var key = arr[i]
        if (map[key]) {
          map[key] += 1
        } else {
          map[key] = 1
        }
      }
      return map
   }
  var arr = ['1','2','3','3','2','2','2','1','3','3','1','1','2','1','1','2']
  console.log(getEleTimes(arr)) // {1: 6, 2: 6, 3: 4}
  console.log(getEleTimes(arr)[1]) // 6