javascript date(leap year) -

javascript date(leap year) -

i have code user inputs start date , automatically add together end date. end date +3 days start date. problem after month of february, march26-31 , outputs wrong end date. output wrong end date 26-31. think problem jump year don't know how prepare it. please help me.

this code:

<input type="date" name="start_date" id="start" onkeyup="date()"> <input type="text" name="end_date" id = "end" onkeyup="date()" disabled /> <script type = "text/javascript"> function date() { var startdate = document.getelementbyid('start'); var enddate = document.getelementbyid('end'); //conver selected stuff proper date format var old = new date(date.parse(startdate.value)); //take new date var newdate=new date(date.parse(startdate.value)+24*60*60*1000*3); // add together how many days want add together utilize 3 can utilize many newdate.setdate(old.getdate()+3); enddate.value = (newdate.getmonth()+1)+'-'+newdate.getdate()+'-'+newdate.getfullyear(); } </script>

this because .setdate() applied on today's date in code, wouldn't work properly. both dates need equal each other before start doing date calculations.

var old = new date(date.parse(startdate.value)), newdate = old; newdate.setdate(old.getdate() + 3);

this work fine stuff jump seconds well.

javascript