I have three drop-down menus for each sample shirt; product, colour and grade. Not all products are available in all colours and/or grades. I would like to disable the options that are not available based on the users selection. I've tried using this answer here (using a radio select). Unfortunately, I can't get it to work with an option-selected input. This is what I'm working on - quartus.ca/select-options.html Any guidance would be appreciated.