A method and system for preserving state in computers communicating over networks, such as the World Wide Web (WWW) using stateless protocols, e.g., HTTP. State is preserved in a conversation between a client requesting services from a served by performing the service and identifying all continuations...http://www.google.com.tw/patents/US5961601?utm_source=gb-gplus-share專利 US5961601 - Preserving state information in a continuing conversation between a client and server networked via a stateless protocol
