convert any time zone to UTC in php

Question

i wants to convert any time zone to UTC i am writing below code but its not working, it is giving same time not converting in UTC can any one help me.

    $triggerOn = '04/01/2013 03:08 PM';
    $user_tz = 'GMT';

    echo $triggerOn; 

    $schedule_date = new DateTime($triggerOn, new DateTimeZone($user_tz));
    $schedule_date->setTimeZone(new DateTimeZone('UTC'));
    $triggerOn = $schedule_date->format('Y-m-d H:i:s');

    echo $triggerOn; 

Answer 1

Try this:

$triggerOn = '04/01/2013 03:08 PM';
echo gmdate('Y-m-d H:i:s',strtotime($triggerOn));

Answer 2

    $triggerOn = '04/01/2013 03:08 PM';
    $newdate = new DateTime($triggerOn);
    $newdate->setTimezone(new DateTimeZone("UTC"));
    echo $newdate->format("Y-m-d H:i:s e") . "\n";