显示建站运行时间:

<span>
    本站已运行
</span>
<span id="span_dt_dt">
</span>
<script>
    /*建站时间*/
    function show_date_time() {
        window.setTimeout("show_date_time()", 1e3);
        var BirthDay = new Date("2018/03/01"),
        today = new Date,
        timeold = today.getTime() - BirthDay.getTime(),
        msPerDay = 864e5,
        e_daysold = timeold / msPerDay,
        daysold = Math.floor(e_daysold),
        e_hrsold = 24 * (e_daysold - daysold),
        hrsold = Math.floor(e_hrsold),
        e_minsold = 60 * (e_hrsold - hrsold),
        minsold = Math.floor(60 * (e_hrsold - hrsold)),
        seconds = Math.floor(60 * (e_minsold - minsold));
        span_dt_dt.innerHTML = daysold + "天" + hrsold + "小时" + minsold + "分" + seconds + "秒";
    }
    show_date_time();
</script>

当前系统时间:

当前系统时间
<span id="nowTime"></span>
<script type="text/javascript">
//获取系统时间
var newDate = '';
getLangDate();
//值小于10时，在前面补0
function dateFilter(date){
    if(date < 10){return "0"+date;}
    return date;
}
function getLangDate(){
    var dateObj = new Date(); //表示当前系统时间的Date对象
    var year = dateObj.getFullYear(); //当前系统时间的完整年份值
    var month = dateObj.getMonth()+1; //当前系统时间的月份值
    var date = dateObj.getDate(); //当前系统时间的月份中的日
    var day = dateObj.getDay(); //当前系统时间中的星期值
    var weeks = ["星期日","星期一","星期二","星期三","星期四","星期五","星期六"];
    var week = weeks[day]; //根据星期值，从数组中获取对应的星期字符串
    var hour = dateObj.getHours(); //当前系统时间的小时值
    var minute = dateObj.getMinutes(); //当前系统时间的分钟值
    var second = dateObj.getSeconds(); //当前系统时间的秒钟值
    var timeValue = "" +((hour >= 12) ? (hour >= 18) ? "晚上" : "下午" : "上午" ); //当前时间属于上午、晚上还是下午
    newDate = dateFilter(year)+"年"+dateFilter(month)+"月"+dateFilter(date)+"日 "+" "+dateFilter(hour)+":"+dateFilter(minute)+":"+dateFilter(second);
    document.getElementById("nowTime").innerHTML = timeValue+"好！当前时间为： "+newDate+"　"+week;
    setTimeout("getLangDate()",1000);
}
</script>

当前时间:

function showtime(times) { //传入时间的参数
    var time_1 = new Date(times).getTime();
    var time_2 = new Date().getTime();
    var time_3;
    var time_distance;
    //计算时间差 
    if (time_1 > time_2) {
        time_distance = time_1 - time_2;
    } else {
        time_distance = time_2 - time_1;
    }
    if (time_distance > 0) {
        // 天时分秒换算 
        var int_day = Math.floor(time_distance / 86400000);
        time_distance -= int_day * 86400000;
        var int_hour = Math.floor(time_distance / 3600000);
        time_distance -= int_hour * 3600000;
        var int_minute = Math.floor(time_distance / 60000);
        time_distance -= int_minute * 60000;
        var int_second = Math.floor(time_distance / 1000);
        // 时分秒为单数时、前面加零 
        if (int_day < 10) {
            int_day = "0" + int_day;
        }
        if (int_hour < 10) {
            int_hour = "0" + int_hour;
        }
        if (int_minute < 10) {
            int_minute = "0" + int_minute;
        }