The 2014-03-03T... notation is a fancy JavaScript Date Time String Format and expects a time zone. If you don't provide one, it defaults to Z (UTC).
The 2014-03-03 18:30:00 notation, however, is just a regular string without an interesting name and, if you don't provide a time zone, it assumes local time.
This info was taken from the MDN article about Date.parse().
Link: https://stackoverflow.com/questions/22151477/javascript-iso-8601-string-into-date-object