How to link css loader before a page loads?

Answer 1

I see 2 approach using javascript:

-Your index page is the css animation. While it's playing you preload the next page. When the loading is complete you redirect the visitor on the welcome page for example.

-You play the animation in front of the welcome page while the content is loading. On complete you destroy the "layer" containing the animation to let appear the welcome page just behind.

Answer 2

Can you provide me the code?