Hourglass or other item to show that the user's request is processing

We frequently have users who have duplicate facilities requests come through because the MLS webpage does not show that their request is being processed once the press the submit button. Because no hourglass, spinning icon, etc. is there to show them that their request is being processed and submitted, they press the submit button a second time. This creates a duplicate request. This is especially problematic when a user make a request for many dates, times, and spaces. It would be great if some action on the webpage showed that the request is in the process of being submitted. Either that, or, if the ability to duplicate the request could be removed, that should also fix the issue.