Drop down lists which display those choices not selected before - within timeframe

Hi I believe I need Java script for this but have zero experience of using it so beginners approach appreciated. I have survey which is essentially being used as contact log of where people have been to interact with our people. This survey contains a drop down list of all available locations. What I would like to happen is the following: Once a location is selected, it is removed from the list until the end of a set period of time, then returns. If this is only feasible within a calendar month - I can live with that. This hopefully will stop a single or select few location repeatedly being visited and others not at all. As a bonus, it would be great if there could be the option to weight them so some location disappear after one visit, others after 2 or 3 and so on, but always returning at the start of the next calendar month/period of time. All help much appreciated.