CloudFlare will make sure the browser can run JS, which in the case of this service I assume it won't. There are ways around this of course, using headless browsers (e.g. PhantomJS), tools like cloudflare-scrape[0] (which uses PyExecJS[1]). I've even used PyQt5 to render webpages for similar purposes.
Unfortunately the aforementioned tools are generally pretty slow (especially headless browsers). Also I can't imagine it's particularly safe running such a service.
Unfortunately the aforementioned tools are generally pretty slow (especially headless browsers). Also I can't imagine it's particularly safe running such a service.
[0]: https://github.com/Anorov/cloudflare-scrape/
[1]: https://github.com/doloopwhile/PyExecJS