<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta http-equiv="X-UA-Compatible" content="ie=edge">
<title>Document</title>
<style>
canvas {
border: 1px solid red
}
</style>
</head>
<body>
<!-- 修改画布得尺寸 -->
<canvas width="800" height="600">我是歌谣</canvas>
<script>
//获取元素
var cans = document.querySelector('canvas');
//获取向下对象
var ctx = cans.getContext('2d')
//指定画布得坐标
ctx.moveTo(100, 100);
//指定终点
ctx.lineTo(300, 100);
//指定线条得颜色
ctx.strokeStyle = 'red';
//指定线条得宽度
ctx.lineWidth = 10;
//描边来化纤
ctx.stroke();
</script>
</body>
</html>
运行结果