function show() {
    var second;
    if (document.getElementById("second").innerHTML == "08") {
        second = 8;
    }
    else if (document.getElementById("second").innerHTML == "09") {
        second = 9;
    }
    else {
        second = parseInt(document.getElementById("second").innerHTML);
    }

    var minutes;
    if (document.getElementById("minutes").innerHTML == "08") {
        minutes = 8;
    }
    else if (document.getElementById("minutes").innerHTML == "09") {
        minutes = 9;
    }
    else {
        minutes = parseInt(document.getElementById("minutes").innerHTML);
    }

    var hour;
    if (document.getElementById("hour").innerHTML == "08") {
        hour = 8;
    }
    else if (document.getElementById("hour").innerHTML == "09") {
        hour = 9;
    }
    else {
        hour = parseInt(document.getElementById("hour").innerHTML);
    }

    var day;
    if (document.getElementById("day").innerHTML == "08") {
        day = 8;
    }
    else if (document.getElementById("day").innerHTML == "09") {
        day = 9;
    }
    else {
        day = parseInt(document.getElementById("day").innerHTML);
    }

    var month;
    if (document.getElementById("month").innerHTML == "08") {
        month = 8;
    }
    else if (document.getElementById("month").innerHTML == "09") {
        month = 9;
    }
    else {
        month = parseInt(document.getElementById("month").innerHTML);
    }

    var dayofweek = document.getElementById("dayofweek").innerHTML;
    var year = parseInt(document.getElementById("year").innerHTML);
    var oSecond;
    var oMinutes;
    var oHour;
    var oDay;
    var oMonth;
    second++;
    if (second == 60) {
        second = 0;
        minutes++;
        if (minutes == 60) {
            minutes = 0;
            hour++;
            if (hour == 24) {
                day++;
                switch (dayofweek) {
                    case "Thứ hai":
                        dayofweek = "Thứ ba";
                        break;
                    case "Thứ ba":
                        dayofweek = "Thứ tư";
                        break;
                    case "Thứ tư":
                        dayofweek = "Thứ năm";
                        break;
                    case "Thứ năm":
                        dayofweek = "Thứ sáu";
                        break;
                    case "Thứ sáu":
                        dayofweek = "Thứ bảy";
                        break;
                    case "Thứ bảy":
                        dayofweek = "Chủ Nhật";
                        break;
                    case "Chủ Nhật":
                        dayofweek = "Thứ hai";
                        break;
                }
                if (day == 29) {
                    if (month == 2) {
                        if (year % 4 != 0) {
                            day = 1;
                            month++;
                        }
                    }
                }
                if (day == 30) {
                    if (month == 2) {
                        if (year % 4 == 0) {
                            day = 1;
                            month++;
                        }
                    }
                }
                if (day == 31) {
                    if (month == 4 || month == 6 || month == 9 || month == 11) {
                        day = 1;
                        month++;
                    }
                }
                if (day == 32) {
                    if (month == 1 || month == 3 || month == 5 || month == 7 || month == 8 || month == 10) {
                        day = 1;
                        month++;
                    }
                    if (month == 12) {
                        day = 1;
                        month = 1;
                        year++;
                    }
                }
            }
        }
    }
    if (second < 10) {
        oSecond = "0" + second;
    }
    else {
        oSecond = second
    }
    if (minutes < 10) {
        oMinutes = "0" + minutes;
    }
    else {
        oMinutes = minutes
    }
    if (hour < 10) {
        oHour = "0" + hour;
    }
    else {
        oHour = hour
    }

    if (day < 10) {
        oDay = "0" + day;
    }
    else {
        oDay = day
    }

    if (month < 10) {
        oMonth = "0" + month;
    }
    else {
        oMonth = month
    }

    document.getElementById("second").innerHTML = oSecond;
    document.getElementById("minutes").innerHTML = oMinutes;
    document.getElementById("hour").innerHTML = oHour;
    document.getElementById("dayofweek").innerHTML = dayofweek;
    document.getElementById("day").innerHTML = oDay;
    document.getElementById("month").innerHTML = oMonth;
    document.getElementById("year").innerHTML = year;
    setTimeout("show()", 1000);
}