话不多说，请看代码：
<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <title>canvas绘制表盘</title> </head> <body> <canvas > 您的浏览器不支持canvas </canvas> <script> var box = document.getElementById('box'); var cxt = box.getContext('2d'); // 时钟动起来 var timer = null; function clock(){ var date = new Date(); var h = date.getHours(); h = h + h/60; h = h>12? h-12:h; var m = date.getMinutes(); var s = date.getSeconds(); // 清画布 cxt.clearRect(0,0,500,500); // 画表盘 cxt.strokeStyle = '#f0f'; cxt.lineWidth = 6; cxt.beginPath(); cxt.arc(250,250,100,0,2*Math.PI); cxt.stroke(); // 画时钟刻度 for(var i=0; i<12; i++){ cxt.save(); cxt.translate(250,250); cxt.rotate(30*i*Math.PI/180); cxt.lineWidth = 3; cxt.beginPath(); cxt.moveTo(0,-80); cxt.lineTo(0,-92); cxt.stroke(); cxt.restore(); } //画分钟刻度 for(var i=0; i<60; i++){ cxt.save(); cxt.translate(250,250); cxt.rotate(6*i*Math.PI/180); cxt.lineWidth = 2; cxt.beginPath(); cxt.moveTo(0,-86); cxt.lineTo(0,-92); cxt.stroke(); cxt.restore(); } // 画时针 cxt.save(); cxt.lineWidth = 5; cxt.translate(250,250); cxt.rotate(h*30*Math.PI/180); cxt.beginPath(); cxt.moveTo(0,6); cxt.lineTo(0,-40); cxt.stroke(); cxt.restore(); // 画分针 cxt.save(); cxt.lineWidth = 3; cxt.translate(250,250); cxt.rotate(m*6*Math.PI/180); cxt.beginPath(); cxt.moveTo(0,8); cxt.lineTo(0,-60); cxt.stroke(); cxt.restore(); // 画秒针 cxt.save(); cxt.lineWidth = 1; cxt.translate(250,250); cxt.rotate(s*6*Math.PI/180); cxt.beginPath(); cxt.moveTo(0,10); cxt.lineTo(0,-75); cxt.stroke(); cxt.restore(); // 画中心的小圆固定三根针 cxt.save(); cxt.beginPath(); cxt.fillStyle = '#0f0'; cxt.lineWidth = 2; cxt.translate(250,250); cxt.arc(0,0,2,0,360,false); cxt.stroke(); cxt.fill(); cxt.restore(); // 画秒针上的园 cxt.save(); cxt.fillStyle = '#f00'; cxt.lineWidth = 2; cxt.translate(250,250); cxt.rotate(s*6*Math.PI/180); cxt.beginPath(); cxt.arc(0,-60,2,0,360,false); cxt.stroke(); cxt.fill(); cxt.restore(); } clock(); timer = setInterval(clock,1000); </script> </body> </html>