Python based browser plug-in?

Is there any good browser plugin that has Python as its primary scripting language. It is ok even if it has very minimal graphical abilities like 开发者_高级运维just taking inputs through HTML forms or parameters and rendering text as output.

One option is running Python on server side. But unfortunately, I am not allowed to install any Python server side framework.

EDIT It seems that Silverlight can use IronPython as its language. But any other more cross platform solutions are still welcome.

You can look at the PyXPCOM add-on to Firefox. It seems to do what you're looking for.