```
this.page.getApp().portal.icon
```
返回的是base64的图标

图标如果要显示在页面上，可以赋值给img的src属性

```
var node = this.target.node;
var img = new Element("img",{"style":"width:100%"}).inject(node);
img.set("src","data:image/png;base64," + this.page.getApp().portal.icon);
```