javascript数组去重

var arr = [1,2,4,5,6,7,7,8,8,8,8],
        arr1 = [],
        obj = {};
for(var i=0; i<arr.length; i++){
    if(!obj[arr[i]]){
        arr1.push(arr[i]);
        obj[arr[i]] = 1;
    }
}
console.log(arr1);

输出结果：[1, 2, 4, 5, 6, 7, 8]