Game Engines in PHP

Is there some good game engines? I'm interested in some PHP or maybe Node.js Game Engine like agar.io or Travian. I really don't know where I can find these, what do you think guys?

There isn't really anyone good once except socket.io which runs it all.
https://github.com/huytd/agar.io-clone
There is an agar clone in socket.io

See on google all the game .io , all same like Agar.io

Unreal Engine has HTML5 export, if that engine was on the table for you.
https://docs.unrealengine.com/latest/INT...ngStarted/

I would not recommend making games in pure PHP as it would probably become very static games and not much dynamic and interactivity. You should Mix in some node.js or JQuery/Javascript to make it alot more realtime and more interactive for the users in this case.