@akapowl It's good for me, just I thought there is a better solution. I found an error, if I scroll down the page than refresh the page I get the following error:
Uncaught ReferenceError: Cannot access 'contentMarkers' before initialization
You can check here: https://cdpn.io/davidtovt/debug/dyzOOPw/bYMdypQgzZRr
Do you know how to fix this?