HTML and CSS Reference
some diferences in browser behavior arising from coding bugs, DOM
misinterpretation, and edge conditions where browser behavior is not
In this topic, whenever you encounter the term DOM, it means the
W3C's drat speciication for HTML5 as interpreted by your favorite
browser. Your browser may or may not support this or that new HTML5
element when you experiment with the examples given. he same is true
of any particular editing tool or environment you like to use. My aim is
to present HTML that works reliably across all modern browsers and is
pleasing to all user agents.
Over the past two decades, HTML has evolved through several iterations—
HTML, HTML2, HTML3, HTML3.2, HTML4, HTML4.1, XHTML. hese
changes have been driven by both standards-setting organizations, such as the
W3C, and individual sotware companies, such as Netscape and Microsot.
HTML5 is the next iteration. Technically, it is not yet a standard, and it will
not be for several years. It is the W3C's working drat for the standard that
it will eventually recommend to oicial standards organizations around the
world. Still, browser manufacturers are already adopting HTML5 features.
For now, HTML5 is best thought of as a directional guide to good standards
of practice in Web design. New HTML5 elements and attributes provide a
richer description of online documents as interactive multimedia spaces. Prior
HTML versions (HTML4 and XHTML) are tied to a print metaphor of a page
to which interactive capabilities and media support have been added ad hoc.
Many pages on the Web are the online equivalent of printed pages. In contrast,
HTML5 encourages a broader conception of the Web as a uniied, intelligent,
interactive, hyperlinked medium.
For online document authors, HTML5 adds new elements to deine docu-
ment sections (the section element) and new section subelements to deine
page headers (header) and footers (footer). Section headings can be composed
of heading groups (hgroup) and can contain the new navigation (nav) element.
HTML4 provided only a single division element (div) for these purposes, and
coders used id and class attributes to make the distinction in usage. here is
a new article element (article) and a means (the aside element) to designate
text that's tangential to the main topic. here is even an element for indicating
sarcastic remarks (sarcasm) in the W3C drat speciication, but I think this is
an inside joke.