Creating a Date Range Array with PHP

I recently needed to come up with an array of dates between two given dates. I typically work in the MySQL-compatible ‘YYYY-MM-DD’ date format, so I wanted it to use dates like that. So I came up with the following function:

function createDateRangeArray($strDateFrom,$strDateTo) {
  // takes two dates formatted as YYYY-MM-DD and creates an
  // inclusive array of the dates between the from and to dates.
  // could test validity of dates here but I'm already doing
  // that in the main script
  $iDateFrom=mktime(1,0,0,substr($strDateFrom,5,2),     substr($strDateFrom,8,2),substr($strDateFrom,0,4));
  $iDateTo=mktime(1,0,0,substr($strDateTo,5,2),     substr($strDateTo,8,2),substr($strDateTo,0,4));
  if ($iDateTo>=$iDateFrom) {
    array_push($aryRange,date('Y-m-d',$iDateFrom)); // first entry
    while ($iDateFrom<$iDateTo) {
      $iDateFrom+=86400; // add 24 hours
  return $aryRange;