note 102293 modified in function.date by danbrown

<?php
// will echo all saturdays found between date range.
function getAllSaturdays($from_date, $to_date){
	// getting number of days between two date range.
	$number_of_days = count_days(strtotime($from_date),strtotime($to_date));
	
	for($i = 1; $i<=$number_of_days; $i++){
		$day = Date('l',mktime(0,0,0,date('m'),date('d')+$i,date('y')));
		if($day == 'Saturday'){
			echo Date('d-m-Y',mktime(0,0,0,date('m'),date('d')+$i,date('y'))),'<br/>';
		}
	}
}
// Will return the number of days between the two dates passed in
function count_days( $a, $b )
{
	// First we need to break these dates into their constituent parts:
	$gd_a = getdate( $a );
	$gd_b = getdate( $b );
	// Now recreate these timestamps, based upon noon on each day
	// The specific time doesn't matter but it must be the same each day
	$a_new = mktime( 12, 0, 0, $gd_a['mon'], $gd_a['mday'], $gd_a['year'] );
	$b_new = mktime( 12, 0, 0, $gd_b['mon'], $gd_b['mday'], $gd_b['year'] );
	// Subtract these two numbers and divide by the number of seconds in a
	// day. Round the result since crossing over a daylight savings time
	// barrier will cause this time to be off by an hour or two.
	return round( abs( $a_new - $b_new ) / 86400 );
}
$from_date = Date('d-m-Y'); // todays date
$to_date = Date('d-m-Y',mktime(0,0,0,date('m'),date('d'),date('y')+1)); // date with one year difference i.e. same date of next year

getAllSaturdays($from_date,$to_date);
?>

--was--
// will echo all saturdays found between date range.
function getAllSaturdays($from_date, $to_date){
	// getting number of days between two date range.
	$number_of_days = count_days(strtotime($from_date),strtotime($to_date));
	
	for($i = 1; $i<=$number_of_days; $i++){
		$day = Date('l',mktime(0,0,0,date('m'),date('d')+$i,date('y')));
		if($day == 'Saturday'){
			echo Date('d-m-Y',mktime(0,0,0,date('m'),date('d')+$i,date('y'))),'<br/>';
		}
	}
}
// Will return the number of days between the two dates passed in
function count_days( $a, $b )
{
	// First we need to break these dates into their constituent parts:
	$gd_a = getdate( $a );
	$gd_b = getdate( $b );
	// Now recreate these timestamps, based upon noon on each day
	// The specific time doesn't matter but it must be the same each day
	$a_new = mktime( 12, 0, 0, $gd_a['mon'], $gd_a['mday'], $gd_a['year'] );
	$b_new = mktime( 12, 0, 0, $gd_b['mon'], $gd_b['mday'], $gd_b['year'] );
	// Subtract these two numbers and divide by the number of seconds in a
	// day. Round the result since crossing over a daylight savings time
	// barrier will cause this time to be off by an hour or two.
	return round( abs( $a_new - $b_new ) / 86400 );
}
$from_date = Date('d-m-Y'); // todays date
$to_date = Date('d-m-Y',mktime(0,0,0,date('m'),date('d'),date('y')+1)); // date with one year difference i.e. same date of next year

getAllSaturdays($from_date,$to_date);

http://php.net/manual/en/function.date.php