Question

I am trying to calculate the time between two times on the current date using JavaScript. There are other questions similar to this one, but none seem to work, and few with many upvotes that I can find.

I have the following, which fails on the line: var diff = new Date(time1 - time2);, which always gives me an invalid Date when alerted, so it is clearly failing. I cannot work out why.

The initial date is added in the format of: hh:mm:ss in an input field. I am using jQuery.

$(function(){

$('#goTime').click(function(){
  var currentDate = new Date();

  var dateString = (strpad(currentDate.getDate()) +'-'+ strpad(currentDate.getMonth()+1)+'-'+currentDate.getFullYear()+' '+ $('#starttime').val());

  var time1 = new Date(dateString).getTime();
  var time2 = new Date().getTime();

  var diff = new Date(time1 - time2);

  var hours = diff.getHours();
  var minutes = diff.getMinutes();
  var seconds = diff.getMinutes();

  alert(hours + ':' + minutes + ':' + seconds);

});
  });
  function strpad(val){ 
        return (!isNaN(val) && val.toString().length==1)?"0"+val:val; 
  }

dateString is equal to: 14-01-2013 23:00

Answer 1

You have the fields in dateString backwards. Swap the year and day fields…

> new Date('14-01-2013 23:00')
Invalid Date
> new Date('2013-01-14 23:00')
Mon Jan 14 2013 23:00:00 GMT-0800 (PST)