<!DOCTYPE html>
<html>
<head>
<canvas id="canvas" width="100" height="100"></canvas>
<script>
var canvas = document.getElementById("canvas");
var ctx = canvas.getContext("2d");
ctx.fillStyle = "rgb(0,128,0)";
ctx.filter = "opacity(0.5)";
ctx.font = "20px serif";
ctx.fillText("Hello world", 0, 50);
</script>
</body></html>
