function dateDiff($dformat, $endDate, $beginDate)
{
$date_parts1=explode($dformat, $beginDate);
$date_parts2=explode($dformat, $endDate);
$start_date=gregoriantojd($date_parts1[0], $date_parts1[1], $date_parts1[2]);
$end_date=gregoriantojd($date_parts2[0], $date_parts2[1], $date_parts2[2]);
return $end_date - $start_date;
}

Now let us see how we use this function:

$date1="07/11/2003";
$date2="09/04/2004";

print "If we minus " . $date1 . " from " . $date2 . " we get " . dateDiff("/", $date2, $date1) . ".";