Currently, this tree should be considered read-only — you can modify it, but this would not make any sense since DomDocument_dump_mem() Currently, this tree should be considered read-only — you can modify it, but this would not make any sense since DomDocument_dump_mem() cannot be applied to it.
This extension is EXPERIMENTAL. The behaviour of this extension -- including the names of its functions and anything else documented about this extension -- may change without notice in a future release of PHP. Use this extension at your own risk.