js 备忘

13966768603

//某年第几周第几天是什么日期
function getXDate(year,weeks,weekDay){
 var date = new Date(year,"0","1");
 var time = date.getTime();
 time+=(weeks-1)*7*24*3600000;
 date.setTime(time);
 weekDay%=7;
 var day = date.getDay();
 var time = date.getTime();
 var sub = weekDay-day;
 time+=sub*24*3600000;
 date.setTime(time);
 return date;
}
//得到某日期属于第几周
function getYearWeek (date) {
 var a=date.getFullYear(),b=date.getMonth(),c=date.getDate();
 var date1 = new Date(a, parseInt(b), c), date2 = new Date(a, 0, 1),
 d = Math.round((date1.valueOf() - date2.valueOf()) / 86400000);
 return Math.ceil((d + ((date2.getDay() + 1) - 1)) / 7);
}