如何在php中获取带时区的日期/时间

I am trying to get a date in this format using php but i cannot find the correct format.

2014-02-20T12:47:39.444-0700

my current code:

 $MTtime = new DateTime('now', new DateTimeZone('America/Denver'));
 $UTCtime = new DateTime('now', new DateTimeZone('UTC'));
 $MTtime->format('Y-m-d H:i:s');
 $UTCtime->format('Y-m-d H:i:s');

how can I achieve this?

thank you @DaOgre for pointing me to the ATOM time format.

here is how I finally got it to work:

$UTCtime = new DateTime('now', new DateTimeZone('UTC'));
$data['logDateTime'] = $UTCtime->format(DateTime::ATOM);

Try using gmDate:

gmDate("Y-m-d\TH:i:s.u-Z");

http://www.php.net/gmdate