HTML.Recommended
            Certain features of the language are necessary for
            compatibility with widespread usage, but they may
            compromise the structural integrity of a document. This
            feature test entity selects a more prescriptive document
            type definition that eliminates those features. It is
            set to `IGNORE' by default.

            For example, in order to preserve the structure of a
            document, an editing user agent may translate HTML
            documents to the recommended subset, or it may require
            that the documents be in the recommended subset for
            import.

    HTML.Deprecated
            Certain features of the language are necessary for
            compatibility with earlier versions of the
            specification, but they tend to be used and implemented
            inconsistently, and their use is deprecated. This
            feature test entity enables a document type definition
            that allows these features. It is set to `INCLUDE' by
            default.




 
RFC 1866            Hypertext Markup Language - 2.0        November 1995


            Documents generated by translation software or editing
            software should not contain deprecated idioms.

1.2.3. User Agents

   An HTML user agent conforms to this specification if:

        * It parses the characters of an HTML document into data
        characters and markup according to [SGML].

            NOTE - In the interest of robustness and
            extensibility, there are a number of widely deployed
            conventions for handling non-conforming documents.
            See 4.2.1, "Undeclared Markup Error Handling" for
            details.

        * It supports the `ISO-8859-1' character encoding scheme and
        processes each character in the ISO Latin Alphabet No. 1 as
        specified in 6.1, "The HTML Document Character Set".

            NOTE - To support non-western writing systems, HTML
            user agents are encouraged to support
            `ISO-10646-UCS-2' or similar character encoding
            schemes and as much of the character repertoire of
            [ISO-10646] as is practical.

        * It behaves identically for documents whose parsed token
        sequences are identical.

        For example, comments and the whitespace in tags disappear
        during tokenization, and hence they do not influence the
        behavior of conforming user agents.

        * It allows the user to traverse (or at least attempt to
        traverse, resources permitting) all hyperlinks from 
        elements in an HTML document.

   An HTML user agent is a level 2 user agent if, additionally:

        * It allows the user to express all form field values
        specified in an HTML document and to (attempt to) submit the
        values as requests to information services.










 
RFC 1866            Hypertext Markup Language - 2.0        November 1995


2. Terms

    absolute URI
            a URI in absolute form; for example, as per [URL]

    anchor
            one of two ends of a hyperlink; typically, a phrase
            marked as an  element.

    base URI
            an absolute URI used in combination with a relative URI
            to determine another absolute URI.

    character