function showWin()
{
    Ext.useShims = true;  //指明浏览器中运用垫片效果
    Ext.onReady(function() {
        var win = new Ext.Window({
                            title: "test flush",
                            modal:true,
                            shim:true,
                            width:390,
                            height:390,
                            resizable: false,
                            autoScroll :'auto',
                            buttonAlign :'left'
        });
        win.show();
    });
}