Position: Fixed in the Webbrowser Control

Hello,

i tried to include a Website to a App with Web browser Control and on the Page is a Image with the CSS Command "" and it doesn't work on Windows Phone 8. I tried different solutions, which i found on the Internet, but none of them work. At the moment i'm using the JQuery Lockfixed Command, but i wanted to know if there's a better way to do it.

I have a Lumia 920 width WP 8.1 on which i tested the page.

Exists a list which command of CSS the Web browser Control support?

Thanks