public function include_script($file, $position='head')
    {
        if (!preg_match('|^https?://|i', $file) && $file[0] != '/') {
            $file = $this->file_mod($this->scripts_path . $file);
        }

        if (!is_array($this->script_files[$position])) {
            $this->script_files[$position] = array();
        }

        if (!in_array($file, $this->script_files[$position])) {
            $this->script_files[$position][] = $file;
        }
    }