Really almost all of this comes down to, "don't use JavaScript to replace HTML". Everything else on this post derives from that one guideline. For example, "Implementing custom div layouts for forms while removing items like select or radio" is only possible if you're replacing native functionality with JavaScript. Which is perfectly fine advice if you aren't doing anything really novel. You probably don't need a cus…
Salient point right here. Being served a blank white page (when JS is disabled) can deter a person from ever visiting a site again. Some peope out there want to vet a site before allowing it to run arbitrary code on their machine.