消除数组重复的元素

思想：用空对象检查原数组中是否有重复的内容

 var arr = [1,2,3,3,4,5,5,6,7,1,9,3,3,25];
    function deRepeat(){
        var newArr = [];
        var obj = {};
        for(var i = 0; i<= arr.length; i++){
            if(obj[arr[i]] == undefined){
                obj[arr[i]]='值';
                newArr.push(arr[i]);
            }
        }
        return  newArr;
    }
    // var newArr2 = deRepeat(arr);
    console.log(deRepeat(arr));