function y2k(number) { return (number < 1000) ? number + 1900 : number; }
function getWeek(year,month,day) {
    var when = new Date(year,month,day);
    var newYear = new Date(year,0,1);
    var offset = 7 + 1 - newYear.getDay();
    if (offset == 8) offset = 1;
    var daynum = ((Date.UTC(y2k(year),when.getMonth(),when.getDate(),0,0,0) - Date.UTC(y2k(year),0,1,0,0,0)) /1000/60/60/24) + 1;
    var weeknum = Math.floor((daynum-offset+7)/7);
    if (weeknum == 0) {
        year--;
        var prevNewYear = new Date(year,0,1);
        var prevOffset = 7 + 1 - prevNewYear.getDay();
        if (prevOffset == 2 || prevOffset == 8) weeknum = 53; else weeknum = 52;
    }
    return weeknum;
}