Who knows a ready-made pre-loader solution?

Question

progress bar

We need such a preloader:
1) A person enters the site
2) The preloader loads the site and after it is fully loaded it shows the person
3) If the site does not load (for example, the server crashed or the Internet disappeared), the preloader does not disappear
I surfed the Internet, did not find a ready-made solution, or something found could not embed, I have such an algorithm for the preloader, it is necessary for a certain chip that I came up with

Answer 1

There is an opinion that this is somewhat contrary to the modern web paradigm, which says that the site should be shown to the user as early as possible.
upd 1 minute on google:
https://niklausgerber.com/blog/preloadme-a-lightwe...
www.inwebson.com/jquery/jpreloader-a-preloading-sc...
goo.gl/3gZHH8

Answer 2

I already answered this question, look in my answers.