https://www.kardland.com uses Javascript and animation for playing a could solitaire card games.
Playing FreeCell for example (https://kardland.com/freecell.html), initially the animation is okay as cards are auto-put-away for the player. But as the game continues it gets more and more sluggish to the point it becomes nearly unplayable.
I have a 92MB screen recording but am apparently unable to attach to this post.