EXTJS遮罩蒙板

var mk = new Ext.LoadMask(tree.id, {msg: '正在更新数据，请稍候！',removeMask: true //完成后移除});mk.show(); //显示Ext.Ajax.request({url: 'roleAction.evi', // 发送get请求.method: 'GET',success: function() {mk.hide(); //关闭},failure: function() { mk.hide(); }});