<!DOCTYPE html><html><body><canvas id="myCanvas" width="200" height="100"style="border:1px solid #d3d3d3;">Your browser does not support the HTML5 canvas tag.</canvas><script type="text/javascript">var c=document.getElementById("myCanvas");var ctx=c.getContext("2d");ctx.beginPath();ctx.arc(95,50,40,0,2*Math.PI);ctx.stroke();</script> </body></html>希望本文所述对大家的web程序设计有所帮助。