http://www.w3schools.com/tags/att_table_rules.asp

Browser Support


The rules attribute is properly displayed in Firefox and Opera.

Internet Explorer, Chrome, and Safari 3 displays this attribute incorrectly .

IE: Adds the four outside borders in addition to the inside borders
Chrome and Safari: Adds the affected outside borders in addition to the inside borders
Note: This attribute is not supported in Safari 2.0 or earlier versions.