Tables - HTML and XHTML: The Definitive Guide - page 647

lhs , and rhs draw the various border segments on the top, bottom, left,
and right side, respectively, of the table. The value hsides draws bor-
ders on the top and bottom (horizontal) sides of the table; vsides draws
borders on the left and right (vertical) sides of the table.
With standard tables now supported by the latest versions of all the pop-
ular browsers, you also may control the thickness of a table's internal
cell borders via the rules attribute. The default behavior, represented
by the value of all , is to draw borders around all cells. Specifying groups
places thicker borders between row and column groups defined by the
<thead>, <tbody>, <tfoot>, <col> , and <colgroup> tags. Using rows or
cols places borders only between every row or column, respectively,
and using none removes borders from every cell in the table.
10.2.1.5. The bordercolor, bordercolorlight, and bordercolordark
attributes
The popular browsers normally draw a table border in three colors, using
light and dark variations on the document's background color to achieve
a 3D effect. Internet Explorer's nonstandard bordercolor attribute lets
you set the color of the table borders and rules to something other than
the background (if borders are enabled, of course). The bordercolor at-
tribute's value can be either an RGB hexadecimal color value or a stand-
ard color name, both of which we describe fully in Appendix G .
Internet Explorer also lets you set the border edge colors individually
with special extension attributes: the bordercolorlight and bordercolor-
dark colors shade the lighter and darker edges of the border. The 3D
beveled-border effect is tied to the relationship between these two col-
ors. In general, the light color should be about 25 percent brighter than
the border color, and the dark color should be about 25 percent darker.
That is, if you use them at all: only your Internet Explorer users will see
the effects.