date function list of js.

count-timezone.js

function calcTime(city, offset) {
        let d       = new Date();
        let utc     = d.getTime() + (d.getTimezoneOffset() * 60000);
        let nd      = new Date(utc + (3600000 * offset));
        let gmtTime = new Date(utc);
        let day     = nd.getDate();
        let month   = nd.getMonth();
        let year    = nd.getYear();
        let hr      = nd.getHours(); //+ offset
        let min     = nd.getMinutes();
        let sec     = nd.getSeconds();
        if (year < 1000) {
            year += 1900;
        }
        let monthArray = [
            "January",
            "February",
            "March",
            "April",
            "May",
            "June",
            "July",
            "August",
            "September",
            "October",
            "November",
            "December"
        ];
        let monthDays  = [
            "31",
            "28",
            "31",
            "30",
            "31",
            "30",
            "31",
            "31",
            "30",
            "31",
            "30",
            "31"
        ];
        if (year % 400 == 0 || (year % 4 == 0 && year % 100 != 0)) {
            monthDays[1] = "29";
        }
        if (hr >= 24) {
            hr = hr - 24;
            day -= -1;
        }
        if (hr < 0) {
            hr -= -24;
            day -= 1;
        }
        if (hr < 10) {
            hr = " " + hr;
        }
        if (min < 10) {
            min = "0" + min;
        }
        if (sec < 10) {
            sec = "0" + sec;
        }
        if (day <= 0) {
            if (month == 0) {
                month = 11;
                year -= 1;
            }
            else {
                month = month - 1;
            }
            day = monthDays[month];
        }
        if (day > monthDays[month]) {
            day = 1;
            if (month == 11) {
                month = 0;
                year -= -1;
            }
            else {
                month -= -1;
            }
        }
        return city + ":The local time is" + monthArray[month] + " " + day + ", " + year + "<br>" + hr + ":" + min + ":" + sec;
//return "The local time in " + city + " is " + nd.toLocaleString()+;
    }

date.js

let d = new Date(),
    c = Date.now();

console.log(d);
// 2016/6/19 上午11:30:40
console.log(d.toLocaleString());

// 2016/6/19
console.log(d.toLocaleDateString());

// Sun Jun 19 2016
console.log(d.toDateString());

// 2016-06-19T03:30:40.096Z
console.log(d.toISOString());

// 上午11:30:40
console.log(d.toLocaleTimeString());

// 11:30:40 GMT+0800 (CST)
console.log(d.toTimeString());

// 2016-06-19T03:30:40.096Z
console.log(d.toJSON());

// Sun, 19 Jun 2016 03:30:40 GMT
console.log(d.toUTCString());

// Sun Jun 19 2016 11:30:40 GMT+0800 (CST)
console.log(d.toString());

// 1466307040096
console.log(c);

// 1,466,307,040,096
console.log(c.toLocaleString());

format-date.js

Date.prototype.pattern = function (fmt) {
    let o    = {
        "M+": this.getMonth() + 1, //月份
        "d+": this.getDate(), //日
        "h+": this.getHours() % 12 == 0 ? 12 : this.getHours() % 12, //小时
        "H+": this.getHours(), //小时
        "m+": this.getMinutes(), //分
        "s+": this.getSeconds(), //秒
        "q+": Math.floor((this.getMonth() + 3) / 3), //季度
        "S" : this.getMilliseconds() //毫秒
    };
    let week = {
        "0": "/u65e5",
        "1": "/u4e00",
        "2": "/u4e8c",
        "3": "/u4e09",
        "4": "/u56db",
        "5": "/u4e94",
        "6": "/u516d"
    };
    if (/(y+)/.test(fmt)) {
        fmt = fmt.replace(RegExp.$1, (this.getFullYear() + "").substr(4 - RegExp.$1.length));
    }
    if (/(E+)/.test(fmt)) {
        fmt = fmt.replace(RegExp.$1, ((RegExp.$1.length > 1) ? (RegExp.$1.length > 2 ? "/u661f/u671f" : "/u5468") : "") + week[this.getDay() + ""]);
    }
    for (let k in o) {
        if (new RegExp("(" + k + ")").test(fmt)) {
            fmt = fmt.replace(RegExp.$1, (RegExp.$1.length == 1) ? (o[k]) : (("00" + o[k]).substr(("" + o[k]).length)));
        }
    }
    return fmt;
}

// let t = new Date(1465068304000);
let t = new Date();
console.log(t.pattern("MMddHHmmyyyy.ss"));
console.log(t.pattern("yyyy-MM-dd HH:mm:ss"));

format-time.js

// format seconds to hh:mm:ss
let formatSeconds = function (value) {
    let sec = parseInt(value);// 秒
    let min = 0;// 分
    let hour = 0;// 小时

    if (sec > 60) {
        min = parseInt(sec / 60);
        sec = parseInt(sec % 60);

        if (min > 60) {
            hour = parseInt(min / 60);
            min = parseInt(min % 60);
        }
    }
    return hour + ':' + min + ':' + sec;
};