Switch to HD version on page load™.
Sorry about my late response, I'm not really checking this website. You need to install Tampermonkey or Greasemonkey extension on your browser then the install button will appear on the page of the script. After that when you visit a gfycat page, it will try to turn on the HD for that video.
I know nothing about coding, can you please explain to me how to use the script?
Thank you