Like table cells, any document body HTML can appear in a caption. Captions are always horizontally centered with respect to the table, and the may have their lines broken to fit within the width of the table. If present, borders are drawn around all table cells. Values are left , center , and right . It can also specify that all the cells in the row should be vertically aligned to the same baseline.
Values are top , middle bottom , and baseline .
Be cautious in use of this attribute as it can result in excessively wide cells. A span that extends into rows that were never specified with a TR will be truncated. We found when creating tables that the creator inevitably wanted a little more control, especially when creating complex multiply nested tables. To this end we added a few more attributes that we are hoping to get into The continually evolving proposed HTML 3.0 spec. First they gain the ability emphasize some tables with respect to others, a table with a border of four containing a sub-table with a border of one looks much nicer than if they both share the same default border width.