From HTML to XHTML

Background

HTML (HyperText Markup Language) is written in SGML (Standard Generalised Markup Language). SGML is the mother of all markup languages and is a massive language to describe markup languages. It has been used to describe languages such as HTML, Rich Text, DocBook and ColdFusion.

HTML is a language to structure information on the Internet. Over the years companies such as Microsoft and Netscape have polluted this structural language with presentational markup and other markup they wanted to provide their own features with.
The general web community became fed up of their pages rendering differently and having to do 300 different versions to deal with all browsers or just lock out those who didn't use the author's browser. So the web community started the Web Standards Initiative - spearheaded by the World Wide Web Consortium (W3C).
This included implementing support for internationalization, a better way of describing layout and presentation (stylesheets) and paving the path of HTML back to just a structure language. HTML 4.0 and 4.01 begins this path with the Strict flavour striping out markup such as applet, iframe, framesets, font and attributes like background, bgcolor, vlink, text, color, target, align, width and height for most elements. I think it was a mistake to remove the target attribute from Strict as it is useful to open webpages in a new tab let-alone a new window. But the Transitional flavour and Frameset flavour retains those depreciated features.

Web browser vendors also wanted an easier way to create new markup. So the web community, based on the experience of HTML, wrote a smaller, stricter version of SGML that could create eXtensible Markup Languages. XML: small enough to be used in many programs and over the Internet, provides the new era of markup languages. A consensus was brought to move HTML from SGML to XML so that it could benefit from the strict document rules and open the doors to new possibilities as eXtensible HyperText Markup Language (XHTML).

Next: XML Structure

Legend Scrolls

From HTML to XHTML

Background