<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>矩形的绘制</title>
</head>
<body>
<canvas id="canvas" width="700" height="500"></canvas>
</body>
<script>
var canvas = document.getElementById('canvas'),
context = canvas.getContext('2d');
context.lineJoin = 'round';
context.lineWidth = 30;
context.font = '24px Helvetica';
context.fillText('点击任何处以擦除', 175, 40);
context.strokeRect(75, 100, 200, 200);
context.fillRect(325, 100, 200, 200);
context.canvas.onmousedown = function (ev) {
context.clearRect(0, 0, canvas.width, canvas.height);
}
</script>
</html>
源码：
