In ARIA 1.1, aria-rowspan and aria-colspan were added. The ARIA spec states the following: If aria-{row,col}span is used on an element for which the host language provides an equivalent attribute, user agents must ignore the value of aria-{row,col}span and instead expose the value of the host language's attribute to assistive technologies. See: * https://rawgit.com/w3c/aria/master/aria/aria.html#aria-rowspan * https://rawgit.com/w3c/aria/master/aria/aria.html#aria-colspan Steps to reproduce: 1. Load data:text/html,<table><tr><th id="test" role="columnheader" rowspan="3" aria-rowspan="2">test cell</th></tr></table> 2. Use Accerciser to examine the element Expected result: "rowspan:2" would not be in the accessible object attributes. Actual result: "rowspan:2" is in the accessible object attributes. 3. Load data:text/html,<table><tr><th id="test" role="columnheader" colspan="3" aria-colspan="2">test cell</th></tr></table> 4. Use Accerciser to examine the element Expected result: "colspan:2" would not be in the accessible object attributes. Actual result: "colspan:2" is in the accessible object attributes.

This is something we should triage and fix but isn't among our most urgent bugs.(Contributions welcome as always!)