Identifying a favicon

Hi,
I want to display favicon from different domains on my page.
I wrote this line (domain is a variable):
<span style="background-image:url('domain/favicon.ico');width:
16px;height:16px;"></span>
Is there a way to display empty favicon when a certain domain does not
have a favicon?
is there a way to know it without round trip to the domain to check it
in advanced?
Thanks, Gabi.