Do you know what the HTML doctype declaration is and why it matters for your web page ... doctypes for each version, such as HTML 2.0, HTML 3.2, HTML 4.01, and XHTML 1.0. Each doctype had a ...

Don't make your customers scroll down a long Web page looking for information about ... attribute which is now considered obsolete in HTML version 5 and Extensible HTML or XHTML.