RFC 1942 (rfc1942) - Page 2 of 30
HTML Tables
Alternative Format: Original Text Document
RFC 1942 HTML Tables May 1996
* alignment on designated characters such as "." and ":"
e.g. aligning a column of numbers on the decimal point
* more flexibility in specifying table frames and rules
* incremental display for large tables as data is received
* the ability to support scrollable tables with fixed headers plus
better support for breaking tables across pages for printing
* optional column based defaults for alignment properties
In addition, a major goal has been to provide backwards compatibility
with the widely deployed Netscape implementation of tables. A
subsidiary goal has been to simplify importing tables conforming to
the SGML CALS model. The latest draft makes the ALIGN attribute
compatible with the latest Netscape and Microsoft browsers. Some
clarifications have been made to the role of the DIR attribute and
recommended behaviour when absolute and relative column widths are
mixed.
A new element COLGROUP has been introduced to allow sets of columns
be grouped with different width and alignment properties specified by
one or more COL elements. The semantics of COLGROUP have been
clarified over previous drafts, and RULES=BASIC replaced by
RULES=GROUPS.
The FRAME and RULES attributes have been modified to avoid SGML name
clashes with each other, and to avoid clashes with the ALIGN and
VALIGN attributes. These changes were additionally motivated by the
desire to avoid future problems if this specification is extended to
allow FRAME and RULES attributes with other table elements.
A Brief Introduction to HTML Tables
Tables start with an optional caption followed by one or more rows.
Each row is formed by one or more cells, which are differentiated
into header and data cells. Cells can be merged across rows and
columns, and include attributes assisting rendering to speech and
braille, or for exporting table data into databases. The model
provides limited support for control over appearence, for example
horizontal and vertical alignment of cell contents, border styles and
cell margins. You can further affect this by grouping rows and
columns together. Tables can contain a wide range of content, such as
headers, lists, paragraphs, forms, figures, preformatted text and
even nested tables.
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