Ext.Ajax.request的waitMsg

var nwin = new Ext.Window({
            title: '编辑',modal : true,closeAction : 'close',buttonAlign : 'center',width : 400,height : 300,layout : 'fit',items: assignmentZDGrid,buttons: [{text: '确定',handler: function(){
                var myMask = new Ext.LoadMask(Ext.getBody(),{
                        msg: '正在保存，请稍后！',removeMask: true //完成后移除
                    });
                myMask.show();
                var ids="";
                var codes="";
                for(var i=0;i <assignmentZDGrid.getStore().getCount();i++)
                {    var id=assignmentZDGrid.getStore().getAt(i).get("type")+":"+assignmentZDGrid.getStore().getAt(i).get("id");
                    ids+=id+",";
                    var code=assignmentZDGrid.getStore().getAt(i).get("codeid");
                    codes+=code+",";
                } 
                Ext.Ajax.request({
                    url : './flow/saveProcessorsForCurrent.html',method : 'POST',params : {ids : ids,codes : codes},success : function(response,options) {
                        var responseArray = Ext.util.JSON.decode(response.responseText);
                            myMask.hide();
                            formView.grid.getStore().load();
                            Ext.Msg.alert('消息',responseArray.msg);
                            nwin.close();
                    }
                });                       

            }},{text: '取消',handler :function(){nwin.close();}}]
    });