Fix some issues under IE8

The `Element.all` method is available under IE8, and can't be overrided it. `el.all` causes an error under IE8.

I use `el.$$` that inspired by Prototypejs' `$$` instead. It means get a list by selector.

`filter` is only available under ES5, but IE8 isn't.

`textContent` not be supported by IE8, use `innerText` instead.