Is the Juris Doctor/Doctor of Jurisprudence/Doctor of Law on a par with the PhD?

Just a professional degree necessary to practice law.

maybe I'm wrong, but I don't think they are equivalent, I think a JD is more of a level between a bachelors and a masters, as once you obtain a JD you can still then add a masters in something like tax law or labor law, before you even get to the PhD level

similar to how civil engineering requires an extra year but isn't really a masters