参照着extjs2.0的文档，效果如何出不来呢

参照着extjs2.0的文档，效果怎么出不来呢？
小弟初步接触extjs,对着文档做个小效果，一直出不来
大神看看是哪错了呢？不胜感激

JScript code

        Ext.onReady(function(){            new Ext.Viewport({                layout:                    "border",                    items:[                    {region:"north",height:50,title:"顶部面板"},                    {region:"south",height:50,title:"底部面板"}，                    {region:"center",title:"中间面板"},                    {region:"west",width:100,title:"左部面板"},                    {region:"east",width:100,title:"右部面板"}                    ]            });        });

JScript code

:"底部面板"}，←───这里的‘，’改为英文半角的‘,’