This is not a terribly exciting example -- which is not suprising, given that I am writing this at around 2:30AM, after approximately 14 hours at the computer, and 20 cups of coffee. Here is the iframe:
I can replace the content of the iframe by selecting the link replace iframe content. This anchor has the attribute target="if_name". The iframe element is labeled by the attribute name="if_name" -- so that selecting this link directs the retrieved resource to this element.