Js计算日期之间的工作日（去掉周六周日）

    //计算日期区间工作日
function countWorkDay(sDay, eDay) {
            var s = new Date(sDay),
                e = new Date(eDay);
            var _sw = s.getDay(),
                _ew = e.getDay();
            console.log(s + "   " + e);
            if (s.getTime() <= e.getTime()) {
                if (s.getTime() == e.getTime() && _sw > 0 && _sw < 6) {
                    console.log("同一天");
                    return 1;
                } else if (s.getTime() == e.getTime() && (_sw == 0 || _sw == 6)) {
                    console.log("同一天周末");
                    return 0
                } else {
                    var diffDay = (e - s) / (1000 * 60 * 60 * 24) + 1;
                    var firWeekday = _sw < 6 && _sw > 0 ? 6 - _sw : 0; //第一周的工作日
                    // console.log(firWeekday);
                    var lastWeekday = (_ew > 0 ? _ew : 0) - (_ew == 6 ? 1 : 0); //最后一周的工作日
                    var diffWeek = (diffDay - firWeekday - lastWeekday) > 0 ? Math.floor((diffDay - firWeekday - lastWeekday) / 7) : 0; //中间的周数
                    // console.log("diff: " + diffWeek);
                    if (diffWeek < 1) {
                        // 周数小于1
                        var __ew = _ew > 5 ? 5 : _ew;
                        var __sw = _sw == 0 ? 1 : _sw;
                        if (__ew >= __sw && diffDay < 7) {
                            // 同一周
                            return __ew - __sw + 1;
                        } else {
                            // 跨周
                            return firWeekday + lastWeekday;
                        }
                    } else {
                        return diffWeek * 5 + firWeekday + lastWeekday;
                    }
                }
            } else {
                return -1; //日期区间错误
            }
        }

      // 测试函数
        function testFun() {
            var _testSD = 1;
            for (var i = 1; i < 8; i++) {
                console.log("第" + i + "次测试");
                for (var j = 1; j < 8; j++) {
                    console.log(countWorkDay("2017/12/" + i, "2017/12/" + j));
                }
            }
        }