Dynamic loading/unloading of off screen DOM elements

When the editor.js block list gets to be pretty large it can start to lag. I am proposing an implementation of dynamic loading/unloading logic of DOM elements based on their presence within or outside of the browser viewport. This reduces the number of DOM elements the browser has to render. Increasing memory, increasing performance, and increases the perceived size of the grid/list.

Examples of some projects that implement this technique are:
http://slickgrid.net/
https://airbnb.io/infinity/
https://github.com/roeierez/infinite-list

I'd like to hear your feedback and encourage the implementation of this technique.