# 20 SGML Declaration of HTML 4.0

Note. The total number of codepoints allowed in the document character set of this SGML declaration includes the first 17 planes of [ISO10646] (17 times 65536). This limitation has been made because this number is limited to a length of 8 digits in the current version of the SGML standard. It does not imply any statement about the feasibility of a long-term restriction of characters in UCS to the first 17 planes. Chances are very high that the limitation to 8 digits in SGML will be removed before, and that this specification will be updated before, the first assignment of a character beyond the first 17 planes.

Note. Strictly speaking, ISO Registration Number 177 refers to the original state of [ISO10646] in 1993, while in this specification, we always refer to the most up-to-date form of ISO 10646. Changes since 1993 have been the addition of characters and a one-time operation reallocating a large number of codepoints for Korean Hangul (Amendment 5).

## 20.1 SGML Declaration

    <!SGML  "ISO 8879:1986"
        --
             SGML Declaration for HyperText Markup Language version 4.0

             With support for the first 17 planes of ISO 10646 and
             increased limits for tag and literal lengths etc.
        --

        CHARSET
              BASESET  "ISO Registration Number 177//CHARSET
                        ISO/IEC 10646-1:1993 UCS-4 with
                        implementation level 3//ESC 2/5 2/15 4/6"
             DESCSET 0       9       UNUSED
                     9       2       9
                     11      2       UNUSED
                     13      1       13
                     14      18      UNUSED
                     32      95      32
                     127     1       UNUSED
                     128     32      UNUSED
                     160     55136   160
                     55296   2048    UNUSED  -- SURROGATES --
                     57344   1056768 57344

    CAPACITY        SGMLREF
                    TOTALCAP        150000
                    GRPCAP          150000
                    ENTCAP          150000

    SCOPE    DOCUMENT
    SYNTAX
             SHUNCHAR CONTROLS 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
               17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 127
             BASESET  "ISO 646IRV:1991//CHARSET
                       International Reference Version
                       (IRV)//ESC 2/8 4/2"
             DESCSET  0 128 0

             FUNCTION
                      RE            13
                      RS            10
                      SPACE         32
                      TAB SEPCHAR    9

             NAMING   LCNMSTRT ""
                      UCNMSTRT ""
                      LCNMCHAR ".-_:"
                      UCNMCHAR ".-_:"
                      NAMECASE GENERAL YES
                               ENTITY  NO
             DELIM    GENERAL  SGMLREF
                      SHORTREF SGMLREF
             NAMES    SGMLREF
             QUANTITY SGMLREF
                      ATTCNT   60      -- increased --
                      ATTSPLEN 65536   -- These are the largest values --
                      LITLEN   65536   -- permitted in the declaration --
                      NAMELEN  65536   -- Avoid fixed limits in actual --
                      PILEN    65536   -- implementations of HTML UA's --
                      TAGLVL   100
                      TAGLEN   65536
                      GRPGTCNT 150
                      GRPCNT   64

    FEATURES
      MINIMIZE
        DATATAG  NO
        OMITTAG  YES
        RANK     NO
        SHORTTAG YES
      LINK
        SIMPLE   NO
        IMPLICIT NO
        EXPLICIT NO
      OTHER
        CONCUR   NO
        SUBDOC   NO
        FORMAL   YES
      APPINFO NONE
    >