本文实例讲述了js+canvas简单绘制圆圈的方法。分享给大家供大家参考，具体如下：
运行效果截图如下：
具体代码如下：
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <title>canvas画圆圈</title> <script type="text/javascript" > function drawCircle(id){ var canvas = document.getElementById(id); if(canvas ) { var context = canvas.getContext("2d"); context.fillStyle = "gray"; context.strokeStyle = "black"; context.fillRect(0, 0, 400, 400); context.beginPath(); context.arc(100, 100, 50, 0, Math.PI*2, true); context.closePath(); context.fillStyle = "green"; context.fill(); } else { return; } } window.onload = function () { drawCircle("canvas"); } </script> </head> <body> <canvas id="canvas" width="400" height="400"></canvas> <hr /> </body> </html>
希望本文所述对大家JavaScript程序设计有所帮助。