Unhiding a div when a lower frame loads

[laredotornado]

Hello,

Could you help me write a cross-browser (IE/Firefox) function that will
live in an upper frame? There is a DIV named "Notebook" in the upper
frame that I would like to remain hidden until the lower frame loads
any other page but the default page, "loading.jsp".

<frameset>
<frame src="controls.jsp" name="upperframe">
<frame src="loading.jsp" name="lowerFrame">
</frameset>

So when the src of the lower frame changes from "loading.jsp" to
anything else, I'd like to unhide (display) the DIV in my upper frame.

How would I do this? Thanks ,- Dave