The invention introduces a method for working collaboratively, performed by a processing unit when loading and executing program code of a client, including: receiving a signal indicating an edit made to an electronic file by a user through an MMI (Man Machine Interface); generating and executing an editing command corresponding to the signal; increasing a client revision counter by one in response to the editing; issuing a synchronization request including the editing command to a server; receiving from the server an acknowledgement including the editing command and a value of a server revision counter; and when a value of the client revision counter corresponding to the editing command does not match the value of the server revision counter, determining that a command conflict has occurred and performing a conflict-resolution procedure to synchronize an execution order of the editing commands from all clients.