A simple ad rotation program written in php, which uses a simple text file to revolve your ads. No need to get any databaseor CGI scripting. You canalso use this concept to revolve contents on your site.
Now to put these two inside the text file, you need to seperate them using ~ sign. like below:
//opening the text file, if this line gives you error when compiling
//the code then you need to chmod 755 your text file
$fcontents = join ('', file ('textfile.txt'));
//Spliting contents of file by looking for ~ mark between codes
//and storing everything into an array.
$s_con = split("~",$fcontents);
//getting a random number which will be within the limit of the
//contents of the file, means if 5 different banners/ads then the number
//will be between 0-4 (total 5 )
$banner_no = (rand()%(count($s_con)-1));
//simple scho banner