javascript - 无法比较星期五日期 JavaScript

Question

您好，我有一个场景，我需要获取过去两周内售出的书籍数量。我正在使用 Javascript 来实现这一点。直到今天一切都运转良好。当日期是星期五时，比较失败。下面是示例。

   //Function to get Monday of thisweek,last week and last to last week.
       function GetMonday(mday) {
         var today, todayNumber, mondayNumber, monday;
         today = new Date();
         todayNumber = today.getDay();
         mondayNumber = mday - todayNumber;
         return new Date(today.getFullYear(), today.getMonth(), today.getDate() + mondayNumber).toDateString();
}


  var currDate = new Date().toDateString(); // gets todays date
  var currwkDate = GetMonday(1); //Gets this week Monday's Date
  var lastwkDate = GetMonday(-6); //Gets last week Monday's Date
  var twowkDate = GetMonday(-13); //Gets Last to last week Monday's Date

  var BillDate=new Date("09/04/2015").toDateString(); // Friday (04 Sep)
          if (currDate == BillDate) {
                 alert("equal");
            }
            if (BillDate > currwkDate) {
                alert("this week");
            }
            if (BillDate > lastwkDate) {
                alert("last week");
            }
            if (BillDate > twowkDate) {
               alert("two week")
            }

理想情况下，上面的代码应该得到三个警报框(本周、上周、两周)，但它甚至不给出单个警报。

如果我编辑上面的代码并将 BillDate 设置为非星期五的任何其他日期，例如，相同的代码将正常工作

   var BillDate= new Date("09/03/2015").toDateString(); //Thursday 03-Sep

我不确定问题是什么，请帮忙!!!!!!

Answer 1

您的代码实际上是在进行字符串比较而不是日期比较。失败的原因是 M从周一开始小于T , W ，和S ，但不是F .

这使得 BillDate > currwkDate如果是星期五，则仅为假。自 F < M 。解决方法是比较日期(删除 toDateString 的使用):

   //Function to get Monday of thisweek,last week and last to last week.
       function GetMonday(mday) {
         var today, todayNumber, mondayNumber, monday;
         today = new Date();
         todayNumber = today.getDay();
         mondayNumber = mday - todayNumber;
         return new Date(today.getFullYear(), today.getMonth(), today.getDate() + mondayNumber);
}


  var currDate = new Date(); // gets todays date
  var currwkDate = GetMonday(1); //Gets this week Monday's Date
  var lastwkDate = GetMonday(-6); //Gets last week Monday's Date
  var twowkDate = GetMonday(-13); //Gets Last to last week Monday's Date

  var BillDate=new Date("09/04/2015"); // Friday (04 Sep)
          if (currDate.getYear() == BillDate.getYear() && currDate.getMonth() == BillDate.getMonth() && currDate.getDate() == BillDate.getDate()) {
                 alert("equal");
            }
            if (BillDate > currwkDate) {
                alert("this week");
            }
            if (BillDate > lastwkDate) {
                alert("last week");
            }
            if (BillDate > twowkDate) {
               alert("two week")
            }

编辑:第一次检查日期是否相等也需要修改为仅检查年、月和日期(忽略小时/等)。