php定义每天发生的事件

我用这段代码每天自动给网站更换一副背景图片存入数据库

// ==========================================================================
//    Creates a file on the server with the day of the month.
//    If the day in the file doesn't match today's date, then do 'event' and update the file.
//
//    I use this to change the daily featured photos from a sql database.
// ==========================================================================
<?PHP 
$dates = (idate("d")); 
$mydate = "getdates.txt"; 
$fh = fopen($mydate, "r"); 
$theDate = fread($fh, 5); 
fclose($fh); 
if ($dates <> $theDate){ 
// Doesn't match what's in the file, so must be a new day. Update file. 
 $fp = fopen('getdates.txt', w); 
 fwrite($fp, $dates); 
 fclose($fp); 
//  Do something. 
} 
// Else ignore. 
?> 
EXAMPLE USE: 
                       $query = "SELECT * FROM `photo_user` WHERE `idno` >'0'"; 
                       $result = mysql_query($query) or die(mysql_error()); 
                                 
                       while($noticia = mysql_fetch_array($result)) 
   { 
                                  // Get total records 
                                  $total = $total +1; 
   } 
// Get current selected user from file. 
$myFile = "getuser.txt"; 
$fh = fopen($myFile, "r"); 
$theData = fread($fh, 5); 
fclose($fh); 
$userNo = $theData; 
// Get today's date. 
$dates = (idate("d")); 
// See what date is in the file. 
$mydate = "getdates.txt"; 
$fh = fopen($mydate, "r"); 
$theDate = fread($fh, 5); 
fclose($fh); 
// Check to see if the dates match. 
  if ($dates <> $theDate){ 
  $userNo = $userNo + 1; 
   if ($userNo > $total){ 
   $userNo = 1; 
} 
// Write today's date to file. 
 $fp = fopen('getdates.txt', w); 
 fwrite($fp, $dates); 
 fclose($fp); 
// Write new user id number to file. 
 $fp = fopen('getuser.txt', w); 
 fwrite($fp, $userNo); 
 fclose($fp); 
} 
?> 
<?php 
                     // Each day a new user is selected. 
                  $query = "SELECT * FROM `photo_user` WHERE `idno` =' ". $userNo."'"; 
                     $result = mysql_query($query) or die(mysql_error()); 
?>