Acid2 is a webpage that test web browsers' functionality in displaying aspects of HTML markup, CSS 2.1 styling, PNG images, and data URIs. The test page was released on 13 April 2005 by the Web Standards Project. The Acid2 test page will be displayed correctly in any application that follows the World Wide Web Consortium and Internet Engineering Task Force specifications for these technologies. These specifications are known as web standards because they describe how technologies used on the web are expected to function.