Question

So I am writing an application using ajax getting from a xml based api. The api returns dates in the following format:

2011-11-12T13:00:00-07:00

I need to get this as a standard JavaScript date object

var myDate = new Date('2011-11-12T13:00:00-07:00');

which works great in every browser BUT ie8 and ie7. I just don’t understand why and can’t seem to find any documentation on how to format this specifically for ie7-8. I know there has to be a smart way to do this. Please help. Thanks.

Answer 1

The only smart way is to parse the string and manually create a date object. It’s not hard:

var dateString = '2011-11-12T13:00:00-07:00';

function dateFromString(s) {
  var bits = s.split(/[-T:]/g);
  var d = new Date(bits[0], bits[1]-1, bits[2]);
  d.setHours(bits[3], bits[4], bits[5]);

  return d;
}

You probably want to set the time for the location, so you need to apply the timezone offset to the created time object, it’s not hard except that javascript date objects add the offset in minutes to the time to get UTC, whereas most timestamps subtract the offset (i.e. -7:00 means UTC – 7hrs to get local time, but the javascript date timezone offset will be +420).

Allow for offset:

function dateFromString(s) {
  var bits = s.split(/[-T:+]/g);
  var d = new Date(bits[0], bits[1]-1, bits[2]);
  d.setHours(bits[3], bits[4], bits[5]);

  // Get supplied time zone offset in minutes
  var offsetMinutes = bits[6] * 60 + Number(bits[7]);
  var sign = /\d\d-\d\d:\d\d$/.test(s)? '-' : '+';

  // Apply the sign
  offsetMinutes = 0 + (sign == '-'? -1 * offsetMinutes : offsetMinutes);

  // Apply offset and local timezone
  d.setMinutes(d.getMinutes() - offsetMinutes - d.getTimezoneOffset())

  // d is now a local time equivalent to the supplied time
  return d;
} 

Of course is it much simpler if you use UTC dates and times, then you just create a local date object, setUTCHours, then date and you’re good to go – the date object will do the timezone thing (provided the local system has it set correctly of course…).