Have a menu option selected on page load, possibly by passing a value through the URL

Can you use PHP/ASP? Or are you limited to HTML only? HTML doesn't have the capacity to capture form-submitted values on its own; if you are using PHP, you'd have to capture the $_GET['select_name'] (which is the value of the selected option for the select tag named "select_name", NOT necessarily the text displayed in that dropdown), and then as you're building the select, test each value against $_GET['select_id_name'] and, if equal, add 'selected="selected"' to the current option's tag. This will make the same option selected before the form is submitted to still be selected after. :)
That is, of course, assuming you're submitting to the same page. ;-)

Can't use PHP, but I'm not limited to HTML. I can use javascript (json) and jconsole. I'm on Apache Tomcat and I don't have access to the server, so my assumption is that I wouldn't be able to use PHP without tweaking something with the server. I've never seen PHP run on Tomcat without some server-side tweaking. I have used PHP on Apache.

ok, well...then you should be good. :) You'll have to do some server-side processing, as JS doesn't have the ability to capture POST & GET params...afaik...

@bigdogdman

Besides PHP, do  you know of any other client-side scripting that can be used? And that doesn't require changes at the server level?

Anyone else?