abc < def     => "abc ","<"," def"
    abc < def    => "abc ","<"," def"

   An ampersand is only recognized as markup when it is followed by a
   letter or a `#' and a digit:

    abc & lt def    => "abc & lt def"
    abc &# 60 def    => "abc &# 60 def"

   A useful technique for translating plain text to HTML is to replace
   each '<', '&', and '>' by an entity reference or numeric character
   reference as follows:

                     ENTITY      NUMERIC
           CHARACTER REFERENCE   CHAR REF     CHARACTER DESCRIPTION
           --------- ----------  -----------  ---------------------
             &       &       &        Ampersand
             <       <        <        Less than
             >       >        >        Greater than

        NOTE - There are SGML mechanisms, CDATA and RCDATA
        declared content, that allow most `<', `>', and `&'
        characters to be entered without the use of entity
        references. Because these mechanisms tend to be used and
        implemented inconsistently, and because they conflict




 
RFC 1866            Hypertext Markup Language - 2.0        November 1995


        with techniques for reducing HTML to 7 bit ASCII for
        transport, they are deprecated in this version of HTML.
        See 5.5.2.1, "Example and Listing: XMP, LISTING".

3.2.2. Tags

   Tags delimit elements such as headings, paragraphs, lists, character
   highlighting, and links. Most HTML elements are identified in a
   document as a start-tag, which gives the element name and attributes,
   followed by the content, followed by the end tag. Start-tags are
   delimited by `<' and `>'; end tags are delimited by `'. An
   example is:

   This is a Heading

   Some elements only have a start-tag without an end-tag. For example,
   to create a line break, use the `' tag.  Additionally, the end
   tags of some other elements, such as Paragraph (`'), List Item
   (`'), Definition Term (`'), and Definition Description
   (`') elements, may be omitted.

   The content of an element is a sequence of data character strings and
   nested elements. Some elements, such as anchors, cannot be nested.
   Anchors and character highlighting may be put inside other
   constructs. See the HTML DTD, 9.1, "HTML DTD" for full details.

      NOTE - The SGML declaration for HTML specifies SHORTTAG YES, which
      means that there are other valid syntaxes for tags, such as NET
      tags, `<EM/.../'; empty start tags, `<>'; and empty end-tags,
      `'. Until support for these idioms is widely deployed, their
      use is strongly discouraged.

3.2.3. Names

   A name consists of a letter followed by letters, digits, periods, or
   hyphens. The length of a name is limited to 72 characters by the
   `NAMELEN' parameter in the SGML declaration for HTML, 9.5, "SGML
   Declaration for HTML". Element and attribute names are not case
   sensitive, but entity names are.  For example, `',
   `', and `' are equivalent, whereas `&' is
   different from `&'.

   In a start-tag, the element name must immediately follow the tag open
   delimiter `<'.








 
RFC 1866            Hypertext Markup Language - 2.0        November 1995


3.2.4. Attributes

   In a start-tag, white space and attributes are allowed between the
   element name and the closing delimiter. An attribute specification
   typically consists of an attribute name, an equal sign, and a value,
   though some attribute specifications may be just a name token. White
   space is allowed around the equal sign.

   The value of the attribute may be either: