Hi @SamuelChang,

You can pull the values of the MRVS in a client script, but you cannot listen for the onChange event from outside of the MRVS. I recently implemented a similar solution and I referred to https://www.servicenow.com/community/developer-forum/impossible-onchange-client-script-on-mrvs-multi... for the solution. Please go through the solution from the community article and let me know if you need a hand with script.