<!DOCTYPE html>
<html>
<body>
<h1>Control LED light</h1>
<p><input type="checkbox" id="light"></p>
<script src="https://cdnjs.cloudflare.com/ajax/libs/socket.io/2.0.3/socket.io.js"></script> <!-- include socket.io client side script -->
<script>
var socket = io(); //load socket.io-client and connect to the host that serves the page
window.addEventListener("load", function(){ //when page loads
var lightbox = document.getElementById("light");
lightbox.addEventListener("change", function() { //add event listener for when checkbox changes
socket.emit("light", Number(this.checked)); //send button status to server (as 1 or 0)
});
});
socket.on('light', function (data) { //get button status from client
document.getElementById("light").checked = data; //change checkbox according to push button on Raspberry Pi
socket.emit("light", data); //send push button status to back to server
});
</script>
</body>
</html>