代码如下：
<!DOCTYPE html> <html> <head> <meta content="width=device-width,initial-scale=1"/> <title>canvas clock</title> <style type="text/css"> div{ text-align: center; margin-top: 250px; } #clock{ border: 1px solid #ccc; } </style> </head> <body> <div> <canvas></canvas> </div> <script type="text/javascript"> var dom=document.getElementById("clock"); var ctx=dom.getContext("2d"); var width=ctx.canvas.width; var heigth=ctx.canvas.height; var r=width/2; //描绘时分秒小数和小数点 function drawBackground(){ ctx.save(); ctx.translate(r,r); //中心原点位置 ctx.beginPath(); //起始位置 ctx.lineWidth=10; //圆 ctx.arc(0,0,r-5,0,2*Math.PI,false); ctx.stroke(); var hourNumbers=[3,4,5,6,7,8,9,10,11,12,1,2]; ctx.font="18px Arial"; ctx.textAlign="center"; ctx.textBaseline="middle"; hourNumbers.forEach(function(number,i){ var rad=2*Math.PI/12*i; var x=Math.cos(rad)*(r-30); var y=Math.sin(rad)*(r-30); ctx.fillText(number,x,y); }); for (var i=0;i<60;i++) { var rad=2*Math.PI/60*i; var x=Math.cos(rad)*(r-18); var y=Math.sin(rad)*(r-18); ctx.beginPath(); if(i%5===0){ ctx.fillStyle="#000"; ctx.arc(x,y,2,2*Math.PI,false); }else{ ctx.fillStyle="#ccc"; ctx.arc(x,y,2,2*Math.PI,false); } ctx.fill(); } } //描绘时针 function drawHour(hour,minute){ ctx.save(); ctx.beginPath(); var rad=2*Math.PI / 12 * hour; var mrad=2*Math.PI / 12 / 60 * minute; ctx.rotate(rad + mrad); ctx.lineWidth=6; ctx.lineCap="round"; ctx.moveTo(0,10); ctx.lineTo(0,-r/2); ctx.stroke(); ctx.restore(); } //描绘分针 function drawMinute(minute){ ctx.save(); ctx.beginPath(); var rad=2*Math.PI/60*minute; ctx.rotate(rad); ctx.lineWidth=3; ctx.lineCap="round"; ctx.moveTo(0,10); ctx.lineTo(0,-r+30); ctx.stroke(); ctx.restore(); } //描绘秒针 function drawSecond(second){ ctx.save(); ctx.beginPath(); ctx.fillStyle="#C14543"; var rad=2*Math.PI/60*second; ctx.rotate(rad); ctx.moveTo(-2,20); ctx.lineTo(2,20); ctx.lineTo(1,-r+18); ctx.lineTo(-1,-r+18) ctx.fill(); ctx.restore(); } //中间固定园点 function drawDot(){ ctx.beginPath(); ctx.fillStyle="#fff"; ctx.arc(0,0,3,0,2*Math.PI,false); ctx.fill(); } function draw(){ ctx.clearRect(0,0,width,heigth); var now=new Date(); var hour=now.getHours(); var minute=now.getMinutes(); var second=now.getSeconds(); drawBackground(); drawHour(hour,minute); drawMinute(minute); drawSecond(second); drawDot(); ctx.restore(); } draw(); setInterval(draw,1000) </script> </body> </html>