US Patent 9479613 Maintaining independent states for multiple web browser instances

A method includes receiving a request for a target Web page, the request containing a session identifier (ID) associated with an instance of a Web browser, and determining if the session ID is new or existing. If the session ID is new, the method includes creating a window session object, and initializing the window session object with data defining a state of the instance of the Web browser. If the session ID is existing, the method includes accessing a stored window session object using the session ID, the stored window session object containing data defining a state of the instance of the Web browser, generating the target Web page based on the data, and providing the target Web page to the Web browser.