Chapter 10:

function save_file() {
   global $filename, $filebody, $dir, $PHP_SELF;

   if (file_exists("$dir/$filename")) {
      echo "<SCRIPT>result =
         confirm(\"Overwrite '$dir/$filename'?\");
         if (!result) history.go(-1);</SCRIPT>";
   }

   if ($file = fopen("$dir/$filename", "w")) {
      fputs($file, $filebody);
      fclose($file);
   }
   else {
      error_message("Can't save file $dir/$filename.");
   }
   echo "<SCRIPT>self.location.href='$PHP_SELF?dir=$di r& filename=$filename';</SCRIPT>";
}

When the Cancel button of the JavaScript Confirm() method is pressed, it will falls back to the previous page but it still overwrite the existing file. Why is that???