Why are linkbuttons not grayed out when disabled in FireFox?

Question

Why when I set enabled=false on a button does it not render correctly in Firefox? Instead of graying out the link it is still blue.

[UPDATE]

ASP.net already removes such tags on the link so the only thing that is needed is to grey out he link. In other words a CSS style change not a functionality change.

The following effectively resolved the disabled buttons not showing up as grayed out in firefox and google chrome. I put this into my style sheet and now all my link buttons render correctly.

a[disabled]{
color:Grey !important; text-decoration:none !important; }