14.    Proposed Entities ..................................... 75

1. Introduction

   The HyperText Markup Language (HTML) is a simple data format used to
   create hypertext documents that are portable from one platform to
   another. HTML documents are SGML documents with generic semantics
   that are appropriate for representing information from a wide range
   of domains.





 
RFC 1866            Hypertext Markup Language - 2.0        November 1995


   As HTML is an application of SGML, this specification assumes a
   working knowledge of [SGML].

1.1. Scope

   HTML has been in use by the World-Wide Web (WWW) global information
   initiative since 1990. Previously, informal documentation on HTML has
   been available from a number of sources on the Internet. This
   specification brings together, clarifies, and formalizes a set of
   features that roughly corresponds to the capabilities of HTML in
   common use prior to June 1994. A number of new features to HTML are
   being proposed and experimented in the Internet community.

   This document thus defines a HTML 2.0 (to distinguish it from the
   previous informal specifications). Future (generally upwardly
   compatible) versions of HTML with new features will be released with
   higher version numbers.

   HTML is an application of ISO Standard 8879:1986, "Information
   Processing Text and Office Systems; Standard Generalized Markup
   Language" (SGML). The HTML Document Type Definition (DTD) is a formal
   definition of the HTML syntax in terms of SGML.

   This specification also defines HTML as an Internet Media
   Type[IMEDIA] and MIME Content Type[MIME] called `text/html'. As such,
   it defines the semantics of the HTML syntax and how that syntax
   should be interpreted by user agents.

1.2. Conformance

   This specification governs the syntax of HTML documents and aspects
   of the behavior of HTML user agents.

1.2.1. Documents

   A document is a conforming HTML document if:

        * It is a conforming SGML document, and it conforms to the
        HTML DTD (see 9.1, "HTML DTD").

            NOTE - There are a number of syntactic idioms that
            are not supported or are supported inconsistently in
            some historical user agent implementations. These
            idioms are identified in notes like this throughout
            this specification.

        * It conforms to the application conventions in this
        specification. For example, the value of the HREF attribute




 
RFC 1866            Hypertext Markup Language - 2.0        November 1995


        of the  element must conform to the URI syntax.

        * Its document character set includes [ISO-8859-1] and
        agrees with [ISO-10646]; that is, each code position listed
        in 13, "The HTML Coded Character Set" is included, and each
        code position in the document character set is mapped to the
        same character as [ISO-10646] designates for that code
        position.

            NOTE - The document character set is somewhat
            independent of the character encoding scheme used to
            represent a document. For example, the `ISO-2022-JP'
            character encoding scheme can be used for HTML
            documents, since its repertoire is a subset of the
            [ISO-10646] repertoire. The critical distinction is
            that numeric character references agree with
            [ISO-10646] regardless of how the document is
            encoded.

1.2.2. Feature Test Entities

   The HTML DTD defines a standard HTML document type and several
   variations, by way of feature test entities. Feature test entities
   are declarations in the HTML DTD that control the inclusion or
   exclusion of portions of the DTD.