 These web standards defined the W3C recommended formats of world wide web content for over 15 years starting in 1997.Pemberton also served as chair of the XHTML 2 working group until the conclusion of its charter at the end of 2009, after which work on the XML version of HTML was subsumed under the specification of HTML 5

Having chaired the first W3C workshop on stylesheets, Pemberton served as a contributing author of Cascading Style Sheets (CSS) specifications, Level 1, Level 2, and Level 3.Since 1998, CSS has been a cornerstone World Wide Web technology, along with HTML and JavaScript.