数组去重

  一.方法一
  Array.prototype.unique = function(){
            var arr = [];
            for(var i=0;i<this.length;i++){
                if(arr.indexOf(this[i])==-1){
                    arr.push(this[i]);
                }
            }
            return arr;
        }

 var arr1 = [1,2,3,5,1,2,3,5,1,2,8,9];
  console.log(arr1);//[1, 2, 3, 5, 1, 2, 3, 5, 1, 2, 8, 9]
 console.log(arr1.unique());//[1, 2, 3, 5, 8, 9]

  二.方法二

        Array.prototype.unique = function(){
            this.sort();
            var arr = [this[0]];
            for(var i=1;i<this.length;i++){
                if(this[i]!==arr[arr.length-1]){
                    arr.push(this[i]);
                }
            }
            return arr;
        }

        var arr1 = [1,2,3,5,1,2,3,5,1,2,8,9];
        console.log(arr1);//[1, 2, 3, 5, 1, 2, 3, 5, 1, 2, 8, 9]
        console.log(arr1.unique());//[1, 2, 3, 5, 8, 9]