A lifetime ago I made a php game called Invasion of Meridell for Neopets.com. Many years after I left Neopets, players started abusing it with bots, so it was taken down.
But some very enterprising individuals made it for their own enjoyment in Java and then another made it in Javascript and shared it online.
I've never been so thrilled in all my coding career to see such a thing! I think the gameplay is right, too. Check it out:
Invasion of Meridell Javascript.