canvas绘制五角星代码如下:
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>五角星绘制</title>
</head>
<body>
<canvas id="star">
</canvas>
<script type="text/javascript">
var star=document.getElementById('star');
var ctx=star.getContext('2d');
star.width=800;
star.height=800;
var R=300;
var r=150;
ctx.lineWidth=10;
ctx.beginPath();
for(var i=0;i<5;i++){
ctx.lineTo(Math.cos((18+i*72)/180*Math.PI)*R+400,
-Math.sin((18+i*72)/180*Math.PI)*R+400
);
ctx.lineTo(Math.cos((54+i*72)/180*Math.PI)*r+400,
-Math.sin((54+i*72)/180*Math.PI)*r+400);
}
ctx.closePath();
ctx.stroke();
</script>
</body>
</html>