Questions about grid and the use of read-only

The readonly attribute is a propety of grid and of gridcell.   The default 
value of readonly is false.  If I set aria-readonly=true on a grid because 
I do not want to allow cell editing, I am hoping that I do not have to 
also set aria-readonly=true on every grid cell?   I didn't see that 
spelled out in the specification nor in the best practices so I would like 
clarification.  Many grids will not have editable cells.  Adding 
aria-readonly=true to the markup for each cell will add a fair amount to 
the page size, thus, it would be nice if the property on the grid would 
suffice. 

However, what if I want to have a grid that is mostly readonly with the 
exception of a few cells?   Could I mark the grid as readonly=true and 
then mark only the cells I want to be edited as readonly=false? This needs 
clarification in the specification - how does the readonly property on the 
grid interact with the readonly property of contained gridcells?

thanks,
-becky



Becky Gibson
Web Accessibility Architect
                                                       
IBM Emerging Internet Technologies
5 Technology Park Drive
Westford, MA 01886
Voice: 978 399-6101; t/l 333-6101
Email: gibsonb@us.ibm.com
blog: weba11y.com/blog