<!DOCTYPE html>
<html>
<body>
<canvas id="myCanvas" width="300" height="150" style="border:1px solid #d3d3d3;">
您的浏览器不支持 HTML5 canvas 标签。</canvas>
<script>
var c = document.getElementById("myCanvas");var ctx = c.getContext("2d");
ctx.beginPath();
ctx.lineWidth = "6";
ctx.strokeStyle = "red";
ctx.rect(5, 5, 290, 140);
ctx.stroke();
ctx.beginPath();
ctx.lineWidth = "4";
ctx.strokeStyle = "green";
ctx.rect(30, 30, 50, 50);
ctx.stroke();
ctx.beginPath();
ctx.lineWidth = "10";
ctx.strokeStyle = "blue";
ctx.rect(50, 50, 150, 80);
ctx.stroke();
</script>
</body>
</html>