I'm guessing it will not refresh, since sleep mode will lock the phone and hide the browser screen.. not sure though.
Another (rather advanced) thing that you should also know about is the scripting ability. If you know Python, Perl, Ruby, Lua or BeanShell scripting languages, you can write scripts that may act on specific things like phone state, incoming chat, position, etc. For instance, you could write a script that disables all wireless internet connections(?) when you put the phone face down on the table.
More info:
Android Scripting Environment
and an example:
Barcode scanner in 6 lines of Python code