In this paper, we present a method for describing the syntax and semantics of viewcharts. Viewcharts is a visual formalism for describing the dynamic behavior of system components. We define the syntax of viewcharts as attributed graphs and, based on this graph, describe dynamic semantics of viewcharts by object mapping automata. This approach covers many important constructs of viewcharts, including hierarchy of views, ownership of elements, scope, and composition of views in SEPARATE, OR and AND ways. It also covers completion and interlevel transitions as well as history transitions without violating the independence of views. Viewcharts was originally based on statecharts; in this paper we also change the basis of viewcharts to an extended version of Finite State Machine (EFSM).