  In this paper, we study the existence of SRB measures and their properties
for infinite dimensional dynamical systems in a Hilbert space. We show several
results including (i) if the system has a partially hyperbolic attractor with
nontrivial finite dimensional unstable directions, then it has at least one SRB
measure; (ii) if the attractor is uniformly hyperbolic and the system is
topological mixing and the splitting is H\"older continuous, then there exists
a unique SRB measure which is mixing; (iii) if the attractor is uniformly
hyperbolic and the system is non-wondering and and the splitting is H\"older
continuous, then there exists at most finitely many SRB measures; (iv) for a
given hyperbolic measure, there exist at most countably many ergodic components
whose basin contains an observable set.
