Js数组去重

<script>
        var arr = [6, 9, 34, 5, 6, 23, 34, 12];
        var array = [];
        function nrepeat(arr) {
            for (var i = 0; i < arr.length - 1; i++) {
                for (var j = i + 1; j < arr.length; j++) {
                    if (arr[i] == arr[j]) {
                        arr.splice(j, 1);
                        j--;
                    }
                }
            }
            return arr;
        }
        var arr2 = nrepeat(arr);
        console.log(arr2);
    </script>
    //输出
    //Array(6)
	//0: 6    索引对应值
	//1: 9
	//2: 34
	//3: 5
	//4: 23
	//5: 12
	length: 6