3v4l.org

run code in 150+ php & hhvm versions
Bugs & Features
<?php $yr="2018"; $dif=2012-$yr;if($dif < 0) $dif=$dif-1;if($dif > 1) $dif=$dif; $week="01"; $day="Monday"; $day=date("D",strtotime($day)); echo date("Y-m-d", strtotime($yr."W".$week."D ".$day)-(86000*$dif));; ?>
Output for 5.1.0 - 7.1.0
2018-01-07
Output for 5.0.0 - 5.0.5
2017-12-31
Output for 4.3.0 - 4.4.9
1970-01-08