function getParentRole(elm) {
			var role, parent = elm || focusedElement;

			while ((parent = parent.parentNode)) {
				if ((role = getRole(parent))) {
					return role;
				}
			}
		}
Returns the wai role of the parent element of the currently
focused element or specified element.

@private
@param {Element} elm Optional element to get parent role from.
@return {String} Role of the first parent that has a role.