Construction and Pedagogical Use of Digital Archives

Washington University
Construction and Pedagogical
Use of Digital Archives
22 May-3 June 2006

David L. Gants
University of New Brunswick

XHTML Key Points

1. History. The developers of XML sought to design an SGML protocol that combined the sophisticated structural, referential, and procedural properties of existing SGML models with the flexibility of application employed by Web creators. As XML became more popular and Web users discovered its numerous advantages, the need for an XML-compliant version of HTML became apparent. XHTML is an XML conforming version of HTML that can be edited and validated using XML design tools while also operating within the parameters of contemporary Web browsers. The XHTML 1.0 recommendation was issued in 2000 by the W3C and revised in 2002.

2. Main HTML-XHTML Differences.

Documents must be well-formed, i.e. the structural hierarchy of open and close tags must be observed
All element and attribute names must be in lower case
Tag minimization is not allowed, i.e. all non-empty tags must have end tags
Attribute minimization is not allowed and must observe to standard attribute="value" form
All attribute values must be within quotes
Empty tags either must have both open and close tags, e.g. <hr><hr>, or must end />, e.g <br />

The full set of HTML-XHTML differences can be found at the W3C site.

3. Declaring the XHTML DTD. The W3C currently supports three levels of conformance:

Strict, where the mark-up represents the document structure and is free of presentational tagging, relying instead on an associated CSS
Transitional, where both structural and presentational tagging are present
Frameset, for use in documents employing frames (the <frame> tag replaces <body>)

The doctype declarations for each dtd are:

 
	<!DOCTYPE html 
 	    PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
 	    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">

	<!DOCTYPE html 
	     PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
 	    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

	<!DOCTYPE html 
	     PUBLIC "-//W3C//DTD XHTML 1.0 Frameset//EN"
 	    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-frameset.dtd">

In addition, a strictly compliant XHTML document should also contain within the root HTML tag a namespace declaration that refers to the W3 consortium XHTML standards:

	<html xmlns="http://www.w3.org/1999/xhtml">

Washington University Construction and Pedagogical Use of Digital Archives 22 May-3 June 2006

David L. Gants University of New Brunswick

XHTML Key Points

Washington University
Construction and Pedagogical
Use of Digital Archives
22 May-3 June 2006

David L. Gants
University of New Brunswick