<!DOCTYPE html>
<html>
<head>
<meta charset=”utf-8″ />
<title>HTML5 timer</title>
<script src=”/jquery/3.2.1/jquery.min.js”></script>
<style>
.clocks {height: 500px;margin: 25px auto;position: relative;width: 500px; }</style> </head> <body> <header> <h2>HTML5 timer</h2> </header> <div class=”clocks”> <canvas id=”canvas” width=”500″ height=”500″></canvas> </div> </body></html>
<script>var canvas, ctx;
var clockRadius = 250;var clockImage;
function clear() {ctx.clearRect(0, 0, ctx.canvas.width, ctx.canvas.height);}function drawScene() {clear();var date = new Date(); var hours = date.getHours(); var minutes = date.getMinutes(); var seconds = date.getSeconds(); hours = hours > 12 ? hours – 12 : hours; var hour = hours + minutes / 60; var minute = minutes + seconds / 60; ctx.save();ctx.drawImage(clockImage, 0, 0, 500, 500); ctx.translate(canvas.width / 2, canvas.height / 2); ctx.beginPath(); ctx.font = ’36px Arial’; ctx.fillStyle = ‘#000’; ctx.textAlign = ‘center’; ctx.textBaseline = ‘middle’; for (var n = 1; n <= 12; n++) { var theta = (n – 3) * (Math.PI * 2) / 12; var x = clockRadius * 0.9 * Math.cos(theta); var y = clockRadius * 0.9 * Math.sin(theta); ctx.fillText(n, x, y); } ctx.save(); var theta = (hour – 3) * 2 * Math.PI / 12; ctx.rotate(theta); ctx.beginPath(); ctx.moveTo(-15, -5); ctx.lineTo(-15, 5); ctx.lineTo(clockRadius * 0.5, 1); ctx.lineTo(clockRadius * 0.5, -1); ctx.fill(); ctx.restore(); ctx.save(); var theta = (minute – 15) * 2 * Math.PI / 60; ctx.rotate(theta); ctx.beginPath(); ctx.moveTo(-15, -4); ctx.lineTo(-15, 4); ctx.lineTo(clockRadius * 0.8, 1); ctx.lineTo(clockRadius * 0.8, -1); ctx.fill(); ctx.restore(); ctx.save(); var theta = (seconds – 15) * 2 * Math.PI / 60; ctx.rotate(theta); ctx.beginPath(); ctx.moveTo(-15, -3); ctx.lineTo(-15, 3); ctx.lineTo(clockRadius * 0.9, 1); ctx.lineTo(clockRadius * 0.9, -1); ctx.fillStyle = ‘#0f0’; ctx.fill(); ctx.restore(); ctx.restore(); ctx.beginPath(); //画笔开始 ctx.lineWidth = 5; //设置画笔的线宽 ctx.strokeStyle=”blue”; //设置画笔的颜色 ctx.arc(250,250,248,0,360,false); //绘制圆形，坐标250,250 半径200，整圆（0-360度），false表示顺时针 ctx.stroke(); //绘图 ctx.closePath(); //结束画布}$(function(){ canvas = document.getElementById(‘canvas’); ctx = canvas.getContext(‘2d’); clockImage = new Image(); setInterval(drawScene, 1000);});</script>
