extjs动态改变样式

{
    width:438,
    height:440,
    name:'loginDiv',
    ui:'123',
    x: '50%' ,
    y: 200,
    border:true,
    bodyStyle:{
        'border':'#d3d3d3 1px solid',
        'background-color':'#fff',
        'border-radius':'2px'
    }
}

listeners:{
    resize : function() {
        //自动登陆框宽高
        var loginDiv = this.down('[name=loginDiv]');
        var footDiv = this.down('[name=footDiv]');
        var windowX = Ext.getBody().getWidth();
        var windowY = Ext.getBody().getHeight();
        loginDiv.setX(windowX*0.5 - 219);
        loginDiv.setY(windowY*0.5 - 220);
        footDiv.setBodyStyle({
            'padding-left':(windowX*0.5 - 225) + "px"
        })
    }
}