Well her int he Netherlands for Dutch government projects its a guideline

As of 1 September last year, every website built for a government agency is required by law to use:

• valid HTML 4.01 or XHTML 1.0
• CSS and semantic HTML and separation of structure and presentation
• progressive enhancement
• the W3C DOM (instead of the old Microsoft document.all)
• meaningful values of class and id
• meaningful alt attributes on all image

and thats not everything they go even further

Furthermore:

• scripts that work on links should extend the basic link functionality (think accessible popups)
• if a link makes no sense without a script, it shouldn't be in the HTML (but be generated by JavaScript)
• use of forms or scripts as the only means of getting certain information is prohibited
• removing the focus rectangle on links is prohibited
• information offered in a closed format (think Word) should also be offered in an open format
• the semantics of many HTML elements are explicitly defined ( meaning a lot of unordered lists,  paragraphs and only tables for tabualr display of data )

You can read (in Dutch) here

http://webrichtlijnen.overheid.nl/besluit/tekst-besluit-en-toelichting/

The go very far in this and a DNN site out of the box without any modification doenst comply to a lot of the rules for validity, acessibillity and semantically correct use of html

Armand Datema

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