Client-server architectures for allowing web applications to operate even when the client and server are disconnected. Exemplary architectures include a local web engine associated with a local cache which can be separate from a browser cache and browser application. Exemplary data structures include web documents having one or more control commands embedded in the head with manifest code. Exemplary methods include operating web applications when the client is offline, caching web applications, executable code, web documents, security code, and/or remote files, allowing web application access of local files, and operating client/web applications.