<!DOCTYPE html>
<html>
<body>
<h1>globalCompositeOperation = "multiply"</h1>
<p>The "multiply" value will result in a darker picture. Multiplies
the pixels of the top layer with the pixels of the bottom layer.</p>
<canvas id="myCanvas" width="300" height="150" style="border:1px solid grey">
Sorry, your browser does not support canvas.
</canvas>
<script>
const canvas = document.getElementById("myCanvas");
const ctx = canvas.getContext("2d");
ctx.globalCompositeOperation = "multiply";
ctx.fillStyle = "blue";
ctx.fillRect(10, 10, 100, 100);
ctx.fillStyle = "red";
ctx.fillRect(40, 40, 100, 100);
</script>
</body>
</html>