JS将日期转换成当年的周数（work week）

{
    display: ‘Work_Week‘, name: ‘create_time‘, width: 80, render: function (item) {
    　　return getYearWeek(item.create_time);
　　}
}

//获取一年中第几周
        function getYearWeek(date) {
            date = formatTimebytype(date, ‘yyyy-MM-dd‘);//将日期转换成yyyy-mm-dd格式
            date = new Date(date);
            var date2 = new Date(date.getFullYear(), 0, 1);
            var day1 = date.getDay();
            if (day1 == 0) day1 = 7;
            var day2 = date2.getDay();
            if (day2 == 0) day2 = 7;
            d = Math.round((date.getTime() - date2.getTime() + (day2 - day1) * (24 * 60 * 60 * 1000)) / 86400000);
            return Math.ceil(d / 7) + 1;
        }