js 實現獲取當前時間是本年第幾周

1、getYearWeek()

功能：返回日期所在年的週數

代碼：

//計算本年的週數
function getYearWeek(endDate) {
    //本年的第一天
    var beginDate = new Date(endDate.getFullYear(), 0, 1);
    //星期從0-6,0代表星期天，6代表星期六
    var endWeek = endDate.getDay();
    if (endWeek == 0) endWeek = 7;
    var beginWeek = beginDate.getDay();
    if (beginWeek == 0) beginWeek = 7;
    //計算兩個日期的天數差
    var millisDiff = endDate.getTime() - beginDate.getTime();
    var dayDiff = Math.floor(( millisDiff + (beginWeek - endWeek) * (24 * 60 * 60 * 1000)) / 86400000);
    return Math.ceil(dayDiff / 7) + 1;
} 

2、調試

var date=new Date();
var year = date.getFullYear();
var week = getYearWeek(date);
var yearWeek=year + "年" + (week>9?week:"0"+week) + "周";
alert(yearWeek);