Thank you very mutch for your reply,but i am not understoode,why i can't use callback.register,because in document (
luatex.org/svn/trunk/manual/luatex.pdf) it only exists function callback.register to add callback. Why i couldn't nothing print in this callback. It's very important for me print something. For example when i want to do tagged pdf and use your package which name tagpdf,close all opened tags at the end of the page and open it at the start of the next page. Where i can find newest documentation about all tables,attributes and functions,which use in lua only for lualatex? —
Aleksandr Kozlovskiy 1 hour ago