Unless you're large and popular to warrant custom case, spam en-masse is almost always computer generated and certainly without JavaScript support, you can batt

Unless you're large and popular to warrant custom case, spam en-masse is almost always computer generated and certainly without JavaScript support, you can battle it easily. Just add an input with value which is submitted when user has no javascript. Change that value via javascript and check for existance server-side. This has been working well ever since comment spammers became a thing 15 or something years ago. It has not failed me since.