I'm looking for a something that allows me to automatically glean a final fully-qualified URL from a < FORM > on a web page. I don't care if it's an IE plug in, a Java applet, a third party program, whatever. As long as it does the job. Anyone know of one?

More detail:

When you have a web page with a <FORM> on it, that when you click on that final <INPUT TYPE=SUBMIT> button, it basically fashions a URL that contains all of the form's data fields concatenated together with & signs between them.

I often create actual bookmarks with the form data pre-filled-out. For instance, instead of having to fill out the username and password to a site, it's often possible to make a URL along the lines of:

http://www.somesite.com/cgi-bin/login.asp?username=myname&password=mypass

I use this method to log in to this BBS, so that I never have to type my user name and password, even if I've cleared all of my cookies, something I do often. (For those who are interested, the format for the current BBS software is http://empeg.comms.net/php/start_page.php?Loginname=yourname&Loginpass=yourpass&option=Login )

Sometimes, though, it's very complicated to figure out just what that URL needs to be in order to work. It involves digging through a bunch of HTML source code of the original login page and trying to glean which fields are necessary. Often, it requires many parameters on the command line which are hidden or generated by javascript code.

I'm looking for a tool which automates this task of digging through the HTML source code. I'd like to be able to go to a login page, type in my user name and password, but instead of hitting SUBMIT, I would instead run this tool, and it would parse the page's source code (or perhaps even proxy the SUBMIT request, that's probably even easier) and then present me with a nicely formatted URL that I can turn into a bookmark.

Does such a tool exist?