@@ -580,6 +580,7 @@ toAttrs kvs = do
580 return $ map (\(x,y) ->
580 return $ map (\(x,y) ->
581 customAttribute
581 customAttribute
582 (fromString (if not html5 || x `Set.member` html5Attributes
582 (fromString (if not html5 || x `Set.member` html5Attributes
583+ || "epub:" `isPrefixOf` x
583 || "data-" `isPrefixOf` x
584 || "data-" `isPrefixOf` x
585 else "data-" ++ x)) (toValue y)) kvs
586 else "data-" ++ x)) (toValue y)) kvs