Programming Minecraft on the web!
WSMCPI let you communicate with Minecraft with a webpage (through WebSocket)!
(YT video will be added here.)
Download or build wsmcpi-1.1X.X.jar, move it to your Spigot/CraftBukkit plugins/ folder.
In your browser's address bar, enter the Spigot server's address, followed by ":8686". Most likely you are running Spigot locally, so the address should be localhost:8686. Then click Connect button on the page to connect.
There are 3 examples of client, and they are located in client/ folder. They can be used as templates for developing different interfaces that can talk to Minecraft.