选中复选框后，计算两个日期之间的天数

Question

我使用下面的代码，如果选中cb1，则会计算总天数。

如果未选中cb1（默认状态），将排除周末。

我的第一个问题是，一旦cb1被选中，它会在计算中减少一天;第二个问题是当cb1取消选中时它没有显示任何结果。

请帮忙。我参考了this thread。

(function () {
     if (getField("cb1").value != "Off") {
         var Start = this.getField("LeaveFrom").value;
         var End = this.getField("LeaveEnd").value;
         var dStart = util.scand("dd/mm/yyyy H:MM:SS", Start + " 0:00:00");
         var dEnd = util.scand("dd/mm/yyyy H:MM:SS", End + " 0:00:00");
         var diff = dEnd.getTime() - dStart.getTime();
         var oneDay = 24 * 60 * 60 * 1000;
         var days = Math.floor(diff/oneDay);
         event.value = days;
     } else {
         var start = this.getField("LeaveFrom").value; // get the start date value
         var end = this.getField("LeaveEnd").value; // get the end date value
         var start =util.scand("dd/mm/yyyy H:MM:SS", start + " 0:00:00");
         var end = util.scand("dd/mm/yyyy H:MM:SS", end + " 0:00:00");

         event.value = dateDifference(start, end);

         function dateDifference(start, end) {
             if (end < start) return -1;
             // Copy date objects so don't modify originals
             var s = new Date(+start);
             var e = new Date(+end);

             // Get the difference in whole days
             var totalDays = Math.round((e - s) / 8.64e7);
             // Get the difference in whole weeks
             var wholeWeeks = totalDays / 7 | 0;
             // Estimate business days as number of whole weeks * 5
             var days = wholeWeeks * 5;
             // If not even number of weeks, calc remaining weekend days
             if (totalDays % 7) {
                 s.setDate(s.getDate() + wholeWeeks * 7);
                 while (s < e) {
                     s.setDate(s.getDate() + 1);
                     // If day isn't a Friday or Saturday, add to business days
                     if (s.getDay() != 5 && s.getDay() != 6) {
                         ++days;
                     }
                 }
             }
             return days;
         }
     }
})();