var currentViewState;
jsf.ajax.addOnEvent(function(e){
    var xml = e.responseXML;
    var source = e.source;
    var status = e.status;
    if(status === 'success'){
        var response = xml.getElementsByTagName('partial-response')[0];
        if(response !== null){
            var changes = response.getElementsByTagName('changes')[0];
            if(changes != undefined){
                var updates = changes.getElementsByTagName('update');
                if(updates != undefined){
                    for(var i = 0; i< updates.length; i++){
                        var update = updates[i];
                        var id = update.getAttribute('id');
                        if(id === 'javax.faces.ViewState'){
                            currentViewState = update.firstChild.data;
                            //update all forms
                            var forms = document.forms;
                            for(var j = 0; j < forms.length; j++){
                                var form = forms[j];
                                var field = form.elements["javax.faces.ViewState"];
                                if (typeof field == 'undefined') {
                                    field = document.createElement("input");
                                    field.type = "hidden";
                                    field.name = "javax.faces.ViewState";
                                    form.appendChild(field);
                                }
                                field.value = currentViewState;
                            }
                        }
                    }
                }
            }
        }
    }

});