Bullshot! All three are Abrahamic religions! The Old Testiment pre-dates Christ, so what was there before that? The Torah and who is Eloh (or Elohim)? Same God as Jehovah (Christianity) and Allah. "generally"? No, all three accept one god, all three accept that the same God revealed himself to Abraham, among other details.

Have you read anything in the Quran or about Islam?

[Link: en.wikipedia.org]

Islam-

[Link: en.wikipedia.org]

You can't just decide they aren't the same because you don't want to believe it and you're pissed off at one or more of them- the writings of all three have too many commonalities. Muslims believe the Quran is the only unaltered version- I fail to see how that's possible when Muhammad didn't even conjure this religion until the 7th century A.D.- The Middle East didn't use only one language (written or spoken) and the writings are in old Hebrew, Greek and Aramaic, so they needed to be translated to assemble the Bible and Quran.

There's no agreement among most followers because they either don't know or don't care that the three have common basis.

If there's no common basis, why do all three consider Jerusalem to be holy and why have so many fought over it for so long?