js 日期转换

[wzhanjun]

js 日期转换

function getWeekNumber(d) {
    // Copy date so don't modify original
    d = new Date(Date.UTC(d.getFullYear(), d.getMonth(), d.getDate()));
    // Set to nearest Thursday: current date + 4 - current day number
    // Make Sunday's day number 7
    d.setUTCDate(d.getUTCDate() + 4 - (d.getUTCDay()||7));
    // Get first day of year
    var yearStart = new Date(Date.UTC(d.getUTCFullYear(),0,1));
    // Calculate full weeks to nearest Thursday
    var weekNo = Math.ceil(( ( (d - yearStart) / 86400000) + 1)/7);
    // Return array of year and week number
    return [d.getUTCFullYear(), weekNo];
}

Date.prototype.format = function(fmt) {
    var o = {
        "M+" : this.getMonth()+1,                 //月份
        "d+" : this.getDate(),                    //日
        "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
    };
    if(/(y+)/.test(fmt)) {
        fmt=fmt.replace(RegExp.$1, (this.getFullYear()+"").substr(4 - RegExp.$1.length));
    }
    for(var 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;
}

function getDateOfISOWeek(w, y) {
    var simple = new Date(y, 0, 1 + (w - 1) * 7);
    var dow = simple.getDay();
    var ISOweekStart = simple;
    if (dow <= 4)
        ISOweekStart.setDate(simple.getDate() - simple.getDay() + 1);
    else
        ISOweekStart.setDate(simple.getDate() + 8 - simple.getDay());
    return ISOweekStart.format("yyyy-MM-dd");
}