<!DOCTYPE html>
<html>
<head>
<script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1/jquery.min.js"></script>
<script type="text/javascript">
$(document).ready(function() {
var canvas = $("#myCanvas");
var context = canvas.get(0).getContext("2d");
// Global alpha
context.fillStyle = "rgb(63, 169, 245)";
context.fillRect(50, 50, 100, 100);
context.globalAlpha = 0.5;
context.fillStyle = "rgb(255, 123, 172)";
context.fillRect(100, 100, 100, 100);
});
</script>
</head>
<body>
<canvas id="myCanvas" width="500" height="500">
<!-- Insert fallback content here -->
</canvas>
</body>
</html>
【drawing_settings】
