<?php echo Date(Y); ?>

PHP
$date_input = '2003';
$date_output= date( "Y-m-d", mktime( 0, 0, 0, 1, 1, $date_input ));
//date_output = 2003-01-01// 1. create a date instance
$date = new DateTime;

// 2. set the date using the setDate(year, month, date) method on the
//    $date instance
$date->setDate(1999,02,19);
Source

Also in PHP: