Custom page refresh (Javascript?)

Hello Freelancers.

I am making a request to see if someone can create a small application or piece of code, whereby a page will be automatically refreshing every 30 seconds to a minute. Upon refresh, I need to receive some sort of notification when an option in the drop down menu is available. Please let me know if this is possible.

I am refreshing the Oxfam page for volunteering at Glastonbury festival, and sometimes slots do open up, so I need to get there at the moment something becomes available. Screenshot attached.

Please post "I got you" at the top of your bid, so I can avoid bots.
Other bids will be removed.

Thanks
J