Jerusalem is also a Holy Land for Muslims also.
Remember, Islam came from Judaism and Christianity. They believe in all those prophets including Jesus. Plus it is Jerusalem where they have the Al Aqsa Mosque (i think that is what is called), the third most holiest site. The funny thing is, The Wailing Wall (I think the most holy site for Jews) is also in that same exact spot. And under it lies the ruins of an old temple which Israel wants to look into but that can demolish the Mosque, which is one of the reasons why this stupid violence is happening.
thats my 2 cents