The Chicago Manual of Style offers two basic systems. One system is Notes and Bibliography.  This is generally used by writers in literature, history, and the arts.

The other is the Author-Date System. This is generally used by writers in the physical sciences, natural sciences, and social sciences.

From the links on the sidebar, you will find examples of how to cite online resources in the body of your paper and in its bibliography, using either of these two styles of citation.