$string="";
$fileCount=0;
$filePath=$PATH.'/var/www/public_html/'; # Specify the path you want to look in. 
$dir = opendir($filePath); # Open the path
while ($file = readdir($dir)) { 
  if (eregi("\.htm",$file)) {
    $string .= "$file<br />";
    $fileCount++;
  }
}