CI_User_agent::is_browser PHP Method

    public function is_browser($key = NULL)
    {
        if (!$this->is_browser) {
            return FALSE;
        }
        // No need to be specific, it's a browser
        if ($key === NULL) {
            return TRUE;
        }
        // Check for a specific browser
        return isset($this->browsers[$key]) && $this->browser === $this->browsers[$key];
    }