The frontend has been updated recently and does not redirect to the no-javascript version automatically if you have javascript disabled. This is clearly a mistake and should be fixed soon.
For the time being you can access explicitly the no-javascript version at http://xmr.to/nojshttps://xmr.to/nojs
Note that if you access it on its onion address at http://xmrto2bturnore26.onion you will also get the no-javascript version.