关于根据User选择的年和第几周来计算此一周的开始和结束日期:

 

 关于根据User选择的年和第几周来计算此一周的开始和结束日期:

function dateAdd(date, days) {

  return new Date(date.getTime() + 24 * 60 * 60 * 1000 * days );

}

function CalcDate() {

  var StartDate, EndDate;

  var iYear = parseInt(document.Form1.TheYear.value); //TheYear就是上图中的Year（下拉框）

  var iWeek = parseInt(document.Form1.TheWeek.value); //TheWeek就是上图中的Week（下拉框）

  var FirstDateOfYear = new Date(iYear,0,1);

  var LastDateOfYear = new Date(iYear,11,31);

  if (iWeek==1){

       StartDate = FirstDateOfYear;

       EndDate = dateAdd(FirstDateOfYear, 6-FirstDateOfYear.getDay());

  }else{

    var SecondWeek_StartDate = dateAdd(FirstDateOfYear, 7-FirstDateOfYear.getDay());

    StartDate = dateAdd(SecondWeek_StartDate, (iWeek-2)*7);

    EndDate = dateAdd(StartDate, 6);

    if (EndDate>LastDateOfYear) EndDate=LastDateOfYear;

  }

  document.getElementById("FromToDate").innerHTML=StartDate.toLocaleDateString() + " ~ " + EndDate.toLocaleDateString();

}