var arr = [1, 2, 3, 4, 5, 3, 4, 5, 6];
  function uniqueArr(arrParam) {
    var newArr = [];     ------新的数组要写到for循环外面，才是全局变量，否则是局部变量
    for (var i = 0; i < arrParam.length; i++) {
      if (newArr.indexOf(arrParam[i]) == -1) {
        newArr.push(arrParam[i])
      }
    }
    return newArr      ------- return也需要在全部去重之后在return，否则只是return的没一个数
  }
  console.log(‘uniqueArr(arr)=‘, uniqueArr(arr));  // [1,2,3,4,5,6]

  var arr1 = [1, 2, 3, 4, 5, 3, 4, 5, 6];
  function uniqueArr1(arrParam) {
    return Array.from(new Set(arrParam)) 
  }
  console.log(uniqueArr1(arr1))