Why is scroll delayed when overlaying content and iframe?

Question

JavaScript

Hello, friends! I have a background site with a small animation on the icons, a javascript that unfolds a fan, and a canvas drawing via swiffyobject and the runtime.js library. It turned out pretty nice and works. But when the page was filed into an iframe and placed on the content of the site as a background, the scrolling of the page slows down, up and down too. Using the contrary method, we remove weighting elements - and everything is getting better only when all effects are completely turned off, even css animation. Tell me what could be the problem?

Answer 1

It is obvious that in the iframe.