PHP Countdown to Date

Question

How could set a date and get a countdown in PHP? For example if I set the date as 3 December 2PM it would tell me how many days and hours are remaining.

No need for

Answer 1

Did this countdown until the end of the semester:

    $endOfSemester = mktime(15,30,0,5,21,2015);
    $now = time();
    $secondsRemaining = $endOfSemester - $now;

    define('SECONDS_PER_MINUTE', 60);
    define('SECONDS_PER_HOUR', 3600);
    define('SECONDS_PER_DAY', 86400);

    $daysRemaining = floor($secondsRemaining / SECONDS_PER_DAY); //days until end
    $secondsRemaining -= ($daysRemaining * SECONDS_PER_DAY); //update variable

    $hoursRemaining = floor($secondsRemaining / SECONDS_PER_HOUR); //hours until end
    $secondsRemaining -= ($hoursRemaining * SECONDS_PER_HOUR); //update variable

    $minutesRemaining = floor($secondsRemaining / SECONDS_PER_MINUTE); //minutes until end
    $secondsRemaining -= ($minutesRemaining * SECONDS_PER_MINUTE); //update variable

    echo("<h3>There are $daysRemaining days, $hoursRemaining hours, $minutesRemaining minutes, $secondsRemaining seconds until the end of the semester</h3>"); //print message