The present invention is directed to a client-server network system implementing a multi-tier caching strategy for a user to access a document efficiently. When serving a document to client, the document is examined for embedded references to other documents. The embedded references are extracted and then assigned a priority. The referenced documents are preloaded to the client prior to receiving a request for them. The referenced documents are obtained locally from the server cache or obtained from their respective web hosts and transmitted according to the assigned priority.