[html5] html 5 dtd

Henri Sivonen hsivonen at iki.fi
Tue Mar 10 06:36:58 PDT 2009

On Mar 10, 2009, at 15:10, Stephen Caine wrote:

> We are revising an application that uses a dtd for validating and  
> controlling a web form.  Specifically, a user is presented with a  
> list of available tags, each tag is then shown with allowable  
> attributes which are checked for the correct type of entry.  We also  
> eliminate the need for a user to enter closing tags by using a  
> parent/child outline layout.  This works great, but thinking about  
> html 5, we are concerned in that no dtd is envisioned.  What  
> alternatives exists or are contemplated for an html 5 dtd?

The alternative that exists is using an HTML5 validator through a Web  
service interface.

You can run your own instance of the Validator.nu software to avoid  
dependencies on uninterrupted operation of a third-party service and  
to avoid sending your user input to a third party..

> I would also like to know why an html 5 dtd cannot be created?   
> After reading the specification, it appears that html 5 will contain  
> tags and attributes.  Furthermore, it appears that opening/closing  
> tags are still part of the specification.  Can't the html 4 dtd be  
> modified to accommodate html 5?

A DTD would be a woefully imprecise representation of the machine- 
checkable conformance requirements of HTML5. (It's woefully imprecise  
for HTML 4, too.) In DTDs, the content model can't depend on the  
presence of an attribute, so e.g. the content model of <video> can't  
be represented properly.

Henri Sivonen
hsivonen at iki.fi

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