So I found this recommendation, but I can't quite seem to figure out how.

This is the code I originally started with:

   function greySubmits(e) {
      var value = e.srcElement.defaultValue;
      // This doesn't work, but it needs to
      $(e).insert('<input type="hidden" name="commit" value="' + value + '" />');

      // This causes IE to not submit at all
      $$("input[type='submit']").each(function(v) {v.disabled = true;})
   }

   // This works fine
   Event.observe(window, 'load', function() {
     $$("input[type='submit']").each(function(e) {
        Event.observe(e, 'click', greySubmits);
     });
  });

Anyway, I am pretty close, but I can't seem to get any further.

Thanks for any help at all!

Update: Sorry, I guess I wasn't entirely clear. I'd like to disable all of the submit buttons when someone clicks a submit button. But I do need to send along the value of the submit button so the server knows which button I clicked, hence the insert call. (Note: insert does not create a child of the element you call it on.) And then after disabling the submit buttons I need to call the containing form of the submit buttons submit call, as IE will not submit after you disable the button. Does that make sense?