js数组去重

 var attr5 = [1, 4, 7, 1, 7, 9, 4, 6, 4, 0, 3, 7, 13, 16, 18, 13];
    var attr6 = new Array();
    for (var i = 0; i < attr5.length; i++) {
        // document.write(attr5[i])
        // console.log(i);、
           // rep数组用于储存下标
        var rep = [];
        for (var j = i + 1; j < attr5.length; j++) {
            // console.log(j);
            // 使用下标来保存需要对比的数据
            if (attr5[i] === attr5[j]) {
                // 不等于时
                // attr6.push(attr5[i]);
                rep.push(j);
                console.log(rep);
            }
        }
        if (rep.length == 0) {
            // 把后面对比没有重复的值添加到数组中
            attr6.push(attr5[i]);
        }
    }
    document.write(attr6)