Accessibility is a major societal task that is constantly gaining in importance. Websites are no exception here. Even more so, online services for some people are their sole possibility of taking part in social life. Thus accessibility is a vital precondition to allow handicapped people to claim their share of the information age. HTML_CodeSniffer is a tool to check any given website for compliance to given standards. The tool generally works as a bookmarklet and can be invoked while surfing around any given website easily.