Note: You know you saw this one coming. - XHTML (or HTML) and
CSS for marking up and styling information. (XML is commonly
used, although any format will work, including preformatted
HTML, plain text, JSON and even EBML). - The XMLHttpRequest
object to exchange data asynchronously with the web server. In
some Ajax frameworks and in some situations, an IFrame object is
used instead of the XMLHttpRequest object to exchange data with
the web server.