Right now looking over these might be promising (haven’t looked into clean-ness of CLJS interop yet, though): https://www.cssscript.com/best-javascript-form-validator/ . I’m surprised not to see much form-related stuff in Closure; the closest I could find is this: https://github.com/google/closure-library/blob/3d08bd72451ab11676cc68d6bae34fcb8d78adb8/closure/goog/events/inputhandler_test.js