<html><body><h1>HTML5 Canvas</h1><h2>arc() 方法</h2><canvas id="myCanvas" width="200" height="120" style="border:1px solid #d3d3d3;"></canvas><script>const canvas = document.getElementById("myCanvas");const ctx = canvas.getContext("2d");ctx.beginPath();ctx.arc(100,50,50,0,Math.PI);ctx.stroke();</script> </body></html>