Abstract: A system for manipulation of an object-based document by a user at a client device has at least one server computer (177) and a client device (101). The server computer comprises: a library of predefined executable functions (206); a database (204) for storage of objects associated with the document; a guard application (202) executable to apply at least one access permission to at least part of the document, the access permission being associated with a creator of the document; and a server application (133B) executable to: receive a message call from the client device; select at least one executable function from the library associated with the message call; and communicate the at least one executable function to the client device.