PHP automatically generates monthly calendar code

/**
php automatically generates monthly calendar
link: bbs.it-home.org 2013-3-7
*/
function calendar($MM,$YYYY){
    if($MM=="") $MM = date("m");
    if($YYYY=="") $YYYY = date("Y");
    if(checkdate($MM,1,$YYYY)){
        $stringDate = strftime("%d %b %Y",mktime (0,0,0,$MM,1,$YYYY));
        $days = strftime("%d",mktime (0,0,0,$MM+1,0,$YYYY));
        $firstDay = strftime("%w",mktime (0,0,0,$MM,1,$YYYY));
        $lastDay = strftime("%w",mktime (0,0,0,$MM,$days,$YYYY));
        $PRintDays = $days;
        $preMonth = strftime("%m",mktime (0,0,0,$MM-1,1,$YYYY));
        $preYear = strftime("%Y",mktime (0,0,0,$MM-1,1,$YYYY));
        $nextMonth = strftime("%m",mktime (0,0,0,$MM+1,1,$YYYY));
        $nextYear = strftime("%Y",mktime (0,0,0,$MM+1,1,$YYYY));
        print("");        print("");        print("");        print("");        print("");        print("");                $currentDays = 1;        for($a=1;$a<=5;$a++){            print("");            $diffDays = $firstDay-$lastDay;            if($firstDay>$lastDay && $currentDays ==1 && ($diffDays<>1)){                for($x=$lastDay;$x>=0;$x--){                    $printDays = $days-$x;                    print("");                }                for($z=1;$z<$firstDay-$lastDay;$z++){                    print("");                }                for($y=$firstDay;$y<7;$y++){                    print("");                    $currentDays++;                }            } elseif($firstDay!=0 && $currentDays==1){                for($z=1;$z<=$firstDay;$z++){                    print("");                }                for($y=$firstDay;$y<7;$y++){                    print("");                    $currentDays++;                }            } else {                for($u=1;$u<=7 && $currentDays<=$days;$u++){                    print("");                    $currentDays++;                }            }            print("");        }        print("
P
".strftime("%b %Y",mktime (0,0,0,$MM,1,$YYYY))."
N

SunMonTueWedThuFriSat







$printDays


 


$currentDays




 


$currentDays




$currentDays





");
    }
}
?>