Attribute for <TABLE ...>
RULES = NONE | ALL | COLS | ROWS | GROUPS

Usage Recommendation
use it, but don't rely on it

RULES indicates if there should be internal borders in the table. In the next five pages we'll go over each of the values of RULES and demonstrate how they are used.

RULES and FRAME have an annoying way of changing each others defaults. To simplify your life, here's a rule of thumb: if you use RULES also use FRAME and BORDER. It's easier to avoid getting confused.

RULES, and HTML 4.0 attribute, is currently not recognized by Netscape.