Add comments and fix code

Author: lulunac27a

datetime-jsp/datetime.js

@@ -7,12 +7,12 @@ var second = document.querySelector("#second");
 function setCurrentDate() {
     var currentDate = new Date();
     var currentYear = currentDate.getFullYear();
-    var currentMonth = currentDate.getMonth() + 1;
+    var currentMonth = currentDate.getMonth() + 1;//Add 1 to month because 0 is January in JavaScript and 1 in Java
     var currentDay = currentDate.getDate();
     var currentHour = currentDate.getHours();
     var currentMinute = currentDate.getMinutes();
     var currentSecond = currentDate.getSeconds();
-    year.value = currentYear;
+    year.value = currentYear;//set the input values to current local date and time
     month.value = currentMonth;
     day.value = currentDay;
     hour.value = currentHour;
@@ -27,7 +27,7 @@ function setCurrentUtcDate() {
     var currentUtcHour = currentDate.getUTCHours();
     var currentUtcMinute = currentDate.getUTCMinutes();
     var currentUtcSecond = currentDate.getUTCSeconds();
-    year.value = currentUtcYear;
+    year.value = currentUtcYear;//set the input values to current UTC date and time
     month.value = currentUtcMonth;
     day.value = currentUtcDay;
     hour.value = currentUtcHour;