PHP自动生成月历代码

<?php
/* 
Function Written by Nelson Neoh @3/2004. 
For those who wants to utilize this code, please do not remove this remark. 
If you have done any enhancement to this code, please post the copy at http://www.dev-club.com PHP board.  Thank you.

Function usage: calendar(Month,Year)
*/

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,$YYYY));
  print("<table border=\"1\" cellpadding=\"1\" cellspacing=\"1\">");
  print("<tr><th valign=\"top\"><a href=\"".$_SERVER['PHP_SELF']."?NB=".$_GET["NB"]."&MM=".$preMonth."&YY=".$preYear."\">P</a></th>");
  print("<th colspan=\"5\" valign=\"top\">".strftime("%b %Y",mktime (0,0,0,$MM,1,$YYYY))."</th>");
  print("<th valign=\"top\"><a href=\"".$_SERVER['PHP_SELF']."?NB=".$_GET["NB"]."&MM=".$nextMonth."&YY=".$nextYear."\">N</a></th></tr>");
  print("<tr style=\"font-family: Verdana; font-size:x-small\">");
  print("<th>Sun</th><th>Mon</th><th>Tue</th><th>Wed</th><th>Thu</th><th>Fri</th><th>Sat</th></tr>");
 
  $currentDays = 1;
  for($a=1;$a<=5;$a++){
   print("<tr align=\"left\" valign=\"top\" style=\"font-family: Verdana; font-size:x-small\">");
   $diffDays = $firstDay-$lastDay;
   if($firstDay>$lastDay && $currentDays ==1 && ($diffDays<>1)){
for($x=$lastDay;$x>=0;$x--){
  $printDays = $days-$x;
  print("<td>$printDays</td>");
}
for($z=1;$z<$firstDay-$lastDay;$z++){
  print("<td>&nbsp;</td>");
}
for($y=$firstDay;$y<7;$y++){
  print("<td>$currentDays</td>");
  $currentDays++;
}
   } elseif($firstDay!=0 && $currentDays==1){
for($z=1;$z<=$firstDay;$z++){
  print("<td>&nbsp;</td>");
}
for($y=$firstDay;$y<7;$y++){
  print("<td>$currentDays</td>");
  $currentDays++;
}
   } else {
for($u=1;$u<=7 && $currentDays<=$days;$u++){
  print("<td>$currentDays</td>");
  $currentDays++;
}
   }
   print("</tr>");
  }
  print("</table>");
}
}
?>