bBevPJ
canvas {border: 1px solid black};function draw() {
var canvas = document.getElementById("demo");
if (canvas.getContext){
var ctx = canvas.getContext('2d');
ctx.fillStyle = "rgb(200,0,0)";
ctx.fillRect (10, 10, 50, 50);
ctx.fillStyle = "rgba(0, 0, 200, 0.5)";
ctx.fillRect (30, 30, 50, 50);
}
}<body onLoad="draw();">
<canvas id = "demo" width=150 height=150></canvas>
</body>