- mktime: documentation ( source)
- date: documentation ( source)
<?php
$tomorrow = mktime(0,0,0,date("m"),date("d")+1,date("Y"));
$yesterday = mktime(0,0,0,date("m"),date("d")-1,date("y"));
echo "Tomorrow is ".date("Y/m/d", $tomorrow);
echo "yesterday is ".date("d-m-y",$yesterday);
?>