index.html

<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<meta http-equiv="Content-Type" content="text/html; charset=utf-8">

		<style>
			html, body {
				margin: 0px;
				padding: 0px;
				height: 100%;
				width: 100%;
			}

			canvas {
				display: block;
				width: 100%;
				height: 100%;
			}
		</style>
	</head>

	<body>

		<!-- Create the canvas that the C++ code will draw into -->
		<canvas id="canvas" oncontextmenu="event.preventDefault()" tabindex="-1"></canvas>

		<script>
			const canvas = document.querySelector("canvas");

			canvas.width = window.innerWidth;
			canvas.height = window.innerHeight;

		    var Module = {
		        canvas: canvas
		    };
		</script>

		<!-- Call the javascript glue code (index.js) as generated by Emscripten -->
		<script src="main.js"></script>

		<script type='text/javascript'>
			canvas.focus();
		</script>

	</body>
</html>