rfc1942.txt

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RFC 1942                      HTML Tables                       May 1996


   mm denotes millimeters, em denotes em units (equal to the height of
   the default font), and px denotes screen pixels. The default units
   are screen pixels (chosen for backwards compatibility). The number is
   an integer value or a real valued number such as "2.5". Exponents, as
   in "1.2e2", are not allowed.  White space is not allowed between the
   number and the suffix.

   The above set of suffices is augmented for certain elements: "%" is
   used for the WIDTH attribute for the TABLE element. It indicates that
   the attribute specifies the percentage width of the space between the
   current left and right margins, e.g. width="50%". For the COL
   element, "*" is used with the WIDTH attribute to specify relative
   column widths, e.g. width="3*", using the same representation as the
   CALS table model.

The TABLE element

<!ENTITY % Where "(left|center|right)">

<!ELEMENT table - - (caption?, (col*|colgroup*), thead?, tfoot?, tbody+)>

<!ATTLIST table                    -- table element --
        %attrs;                    -- id, lang, dir and class --
        align   %Where;  #IMPLIED  -- table position relative to --
                                   -- window --
        width   CDATA    #IMPLIED  -- table width relative to window --
        cols    NUMBER   #IMPLIED  -- used for immediate display mode --
        border  CDATA    #IMPLIED  -- controls frame width around --
                                   -- table --
        frame   %Frame;  #IMPLIED  -- which parts of table frame to --
                                   -- include --
        rules   %Rules;  #IMPLIED  -- controls rules between cells --
        cellspacing CDATA #IMPLIED -- spacing between cells --
        cellpadding CDATA #IMPLIED -- spacing within cells --
        >

   The TABLE element requires both start and end tags. Table elements
   start with an optional CAPTION element, optionally followed by either
   one or more COL elements, or one or more COLGROUP elements, then an
   optional THEAD, an optional TFOOT, and finally one or more TBODY
   elements.

   ID, CLASS, LANG and DIR
       See earlier description of common attributes.

   ALIGN
       Defines the horizontal position of the table relative to the
       current left and right margins. ALIGN=CENTER centers the table



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       midway between the left and right margins. ALIGN=LEFT positions
       the table at the left margin, while ALIGN=RIGHT positions the
       table at the right margin. User agents may flow text around the
       right handside of the table for ALIGN=LEFT, or the left handside
       for ALIGN=RIGHT.

       Note you can use <BR CLEAR=LEFT> after the table element if you
       want to avoid text flowing along side the table when you have
       specified ALIGN=LEFT, or <BR CLEAR=RIGHT> for a right aligned
       table. To prevent a right aligned table flowing around something
       else, use <BR CLEAR=RIGHT> before the table etc. Greater control
       over textflow is possible using style sheets.

   WIDTH
       Specifies the desired width of the table. In addition to the
       standard units, the "%" sign may used to indicate that the width
       specifies the percentage width of the space between the current
       left and right margins, e.g. width="50%". In the absence of this
       attribute, the table width can be determined by the layout
       algorithm given later on.

       It is recommended that the table width be increased beyond the
       value indicated by the WIDTH attribute as needed to avoid any
       overflow of cell contents. Such increases should try to avoid
       drastic changes to relative column widths specified by the
       author. To avoid the need for excessive horizontal scrolling, or
       when such scrolling is impractical or undesired, it may be
       appropriate to split words across lines.

   COLS
       Specifies the number of columns for the table. If present the
       user agent may render the table dynamically as data is received
       from the network without waiting for the complete table to be
       received. If the WIDTH attribute is missing, a default of "100%"
       may be assumed for this purpose. If the COLS attribute is
       absent, a prepass through the table's contents is needed to
       determine the number of columns together with suitable values
       for the widths of each column.

   BORDER
       Specifies the width of the border framing the table, see
       standard units.

   FRAME
       Specifies which sides of the frame to render.

       <!ENTITY % Frame
          "(void|above|below|hsides|lhs|rhs|vsides|box|border)">



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RFC 1942                      HTML Tables                       May 1996


       VOID
           Don't render any sides of the frame.

       ABOVE
           The top side of the frame

       BELOW
           The bottom side of the frame

       HSIDES
           The top and bottom sides of the frame

       LHS
           The left hand side of the frame

       RHS
           The right hand side of the frame

       VSIDES
           The left and right sides of the frame

       BOX
           All four sides of the frame

       BORDER
           All four sides of the frame

       The value "Border" is included for backwards compatibility with
       deployed browsers. If a document includes <TABLE BORDER> the
       user agent will see FRAME=BORDER and BORDER=_implied_. If the
       document includes <TABLE BORDER=_n_> then the user agent should
       treat this as FRAME=BORDER except if _n=0_ for which FRAME=VOID
       is appropriate.

       Note: it would have been preferable to choose values for FRAME
       consistent with the RULES attribute and the values used for
       alignment. For instance: none, top, bottom, topbot, left, right,
       leftright, all. Unfortunately, SGML requires enumerated
       attribute values to be unique for each element, independent of
       the attribute name. This causes immediate problems for "none",
       "left", "right" and "all". The values for FRAME have been chosen
       to avoid clashes with the RULES, ALIGN and VALIGN attributes.
       This provides a measure of future proofing, as it is anticipated
       that that the FRAME and RULES attributes will be added to other
       table elements in future revisions to this specification. An
       alternative would be to make FRAME a CDATA attribute. The
       consensus of the HTML-WG was that the benefits of being able to
       use SGML validation tools to check attributes based on



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RFC 1942                      HTML Tables                       May 1996


       enumerated values outweighs the need for consistent names.

   RULES
       Specifies where to draw rules within the table interior.

       <!ENTITY % Rules "(none | groups | rows | cols | all)">

       NONE
           Suppresses internal rulings.

       GROUPS
           The THEAD, TFOOT and TBODY elements divide the table into
           groups of rows, while COLGROUP elements divide the table
           into groups of columns. This choice places a horizontal rule
           between each row group and a vertical rule between each
           column group. Note that every table has at least one row and
           one column group.

       ROWS
           As RULES=GROUPS plus horizontal rules between all rows. User
           agents may choose to use a heavier rule between groups of
           rows and columns for emphasis.

       COLS
           As RULES=GROUPS plus vertical rules between all columns.
           User agents may choose to use a heavier rule between groups
           of rows and columns for emphasis.

       ALL
           Place rules between all rows and all columns. User agents
           may choose to use a heavier rule between groups of rows and
           columns for emphasis.

       If a document includes <TABLE BORDER> or <TABLE BORDER=_n_> then
       the default for the table element is RULES=ALL, except if _n=0_
       for which RULES=NONE is appropriate.

   CELLSPACING
       This attribute is intended for backwards compatibility with
       deployed user agents. It specifies the space between the table
       frame and the first or last cell border for each row or column,
       and between other cells in the table. See standard units.
       Greater control will be possible using style sheet languages.

   CELLPADDING
       This attribute is intended for backwards compatibility with
       deployed user agents. It specifies the amount of space between
       the border of the cell and its contents both above/below, and



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RFC 1942                      HTML Tables                       May 1996


       left//right. See standard units. Greater control will be
       possible using style sheet languages.

   If a fixed width is set for the table or column, the CELLSPACING and
   CELLPADDING may demand more space than assigned. Current practice is
   for the latter to take precedence over WIDTH attributes when a
   conflict occurs, although this isn't required by this specification.

Table Captions

   <!ELEMENT caption - - (%text;)+>

   <!ENTITY % Caption "(top|bottom|left|right)">

   <!ATTLIST caption                  -- table caption --
           %attrs;                    -- id, lang, dir and class --
           align   %Caption; #IMPLIED -- relative to table --
           >

   The optional CAPTION element is used to provide a caption for the
   table. Both start and end tags are required.

   ID, CLASS, LANG and DIR
       See earlier description of common attributes.

   ALIGN
       This may be used to control the placement of captions relative
       to the table. When present, the ALIGN attribute should have one
       of the values: TOP, BOTTOM, LEFT and RIGHT. It is recommended
       that the caption is made to fit within the width or height of
       the table as appropriate. The default position of the caption is
       deliberately unspecified.

       Note the ALIGN attribute is overused in HTML, but is retained
       here for compatibility with currently deployed browsers.

The COLGROUP Element

   <!ELEMENT colgroup - O (col*)>

   <!ATTLIST colgroup
           %attrs;                    -- id, lang, dir and class --
           span    NUMBER   1         -- default number of columns in --
                                      -- group --
           width   CDATA    #IMPLIED  -- default width for enclosed --
                                      -- COLs --
           %cell.halign;              -- horizontal alignment in --
                                      -- cells --



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RFC 1942                      HTML Tables                       May 1996


           %cell.valign;              -- vertical alignment in cells --
           >


   The COLGROUP element acts as a container for a group of columns, and
   allows you to set default properties for these columns. In the
   absence of a COLGROUP element, all columns in the table are assumed
   to belong to a single column group. Each COLGROUP element can
   contain zero or more COL elements. COLGROUP requires a start tag,
   but the end tag may be omitted. This is useful when defining a
   sequence of COLGROUP elements, e.g.

       <TABLE FRAME=BOX RULES=COLS>
         <COLGROUP>
           <COL WIDTH="1*">
           <COL WIDTH="2*">
         <COLGROUP>
           <COL WIDTH="1*">
           <COL WIDTH="3*">
         <THEAD>
           <TR> ...
       </TABLE>