JS package implementation based on the start time to calculate the current first few weeks

function Todayinfo (start,today) {var Weeklen = 7, weekdays = [' Day ', ' one ', ' Two ', ' three ', ' four ', ' five ', ' six ', Weekinfo = {' Week '  
        : null, ' Day ': null},//initialization return information, default NULL week, week null oneday = 24 * 60 * 60 * 1000,//milliseconds  Weekleave,///////The number of days remaining on the day of school Weekstart,//The start of the day is the week of DateDiff,//today and the date of the opening day sdate; On the day of school, date object var rdatestr =/\d{4}[\/-]\d{1,2}[\/-]\d{1,2}/g; Simple date format check: xxxx/xx/xx if (!rdatestr.test (start)) {alert (' Please use a valid start date ...
        ');
    return weekinfo;
    } sdate = new Date (Start.replace ('-', '/'));
    Weekstart = Sdate.getday (); Weekstart = Weekstart = = 0? 7:weekstart;
    JS Sunday index is 0, here to 7, to facilitate the calculation of Weekleave = Weeklen-weekstart; Today = new Date (today) | |
    New Date ();
    Weekinfo.day = Weekdays[today.getday ()]; Today = new Date (today.getfullyear () + '/' + (Today.getmonth () + 1) + '/' + today.getdate ());
    DateDiff = today-sdate; if (DateDiff < 0) {alert (start+ ') hasn't started yet.
        ');
    return weekinfo;
    } DateDiff = parseint (Datediff/oneday);
    Weekinfo.week = Math.ceil (datediff-weekleave)/Weeklen) + 1;
return weekinfo;
}//var td = Todayinfo (' 2017/3/1 '); ' First ' + Td.week + ' week, today's week ' + td.day;