You can do it, although you need to go through hoops and you may have browser issues. You need to set up a hidden communication machanism. You can do this by:

1. Making an iframe with style='display: none;'
2. Making a button with style='display: none;'
3. Making a frame with style='display: none;'

You can then use the src or location property of your hidden element to call a cgi script. They cgi script can use the onLoad handler to update the submit button.
In addition you should make the onChange disable the submit button and the onLoad handler reenable it (so that they can't submit while you are calculating).

-pete
"Pain heals. Chicks dig scars. Glory lasts forever."