XHTML Frameset
When the Doctype Declaration attribute value is left blank, this is the default option. When this option is in effect or selected, the following is placed at the beginning of the generated HTML page: <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Frameset//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-frameset.dtd"> This declares the document to be the XML version of HTML 4.01 Frameset. HTML 4 Frameset includes all of the elements and attributes of HTML 4 Transitional and adds support for HTML frames. This is the most "generous" doctype and supports the most features in an HTML document.