- mktime: documentation ( source)
- floor: documentation ( source)
<?php
print ' - ';
$i = mktime(0,0,0,10,14,2013);
$f = mktime(0,0,0,10,28,2013);
print $f;
print ' - ';
print $i;
print ' - ';
print ($f - $i);
print ' - ';
print floor(($f - $i)/86400);
print ' - ';