Judaism stands on its own. Christianity can not stand but for Judaism. Islam plagiarizes both.
This is not the time or place for a discussion of this but I believe that Christianity is a branch of Judaism, historically speaking. Obviously this can only be the case if you take the position that Paul took with James (the brother of Jesus), that certain requirements of Judaism as it existed up till then were inessential.
As we all know, Judaism had a wide range of opinions during the first century. The positions of those who exalted the Sacrifice at the Temple as the heart of Judaism clearly does not have much of a following now. Modern Judaism is descended from Rabbinical Judaism, which started to flourish shortly before the period. Those who were Pharisees clearly divided, with many continuing as Jews, others becoming Christian.
Of course by the beginning of the 2nd century Gentiles started to dominate the Christian church, and Christians ceased attending services at the more tolerant Jewish congregations. As we know, the Romans, who in their own way were non-partisan in this dispute, considered Christianity to be a form of Judaism for more than a century.
I realize that this is off topic, and probably pleases nobody here, but it might be worth a discussion sometime, somewhere. Obviously the major division between Jews and Christians is the question of the nature of the Messiah, and, more directly, is his coming a future, or a past event.