<head>
<meta charset="UTF-8">
<title>使用canvas元素繪制指針式動畫時鐘</title>
<script type="text/javascript">
var canvas;
var context;
//頁面裝載
function window_onload()
{
canvas=document.getElementById("canvas");//獲取canvas元素
context=canvas.getContext('2d');//獲取canvas元素的圖形上下文對象
setInterval("draw()",1000);//每隔壹秒重繪時鐘，重新顯示時間
}
//繪制時鐘
function draw()
{
var radius=Math.min(canvas.width / 2, canvas.height / 2) -25;//時鐘羅盤半徑
var centerx=canvas.width/2;//時鐘中心橫坐標
var centery=canvas.height/2;//時鐘中心縱坐標
context.clearRect(0,0,canvas.width,canvas.height);//擦除之前所繪時鐘
context.save();//保存當前繪制狀態
//繪制時鐘圓盤
context.fillStyle = '#efefef';//時鐘背景色
context.strokeStyle = '#c0c0c0';//時鐘邊框顏色
context.beginPath();//開始創建路徑
context.arc(centerx,centery,radius, 0,Math.PI*2, 0);//創建圓形羅盤路徑
context.fill();//用背景色填充羅盤
context.stroke();//用邊框顏色繪制羅盤邊框
context.closePath();//關閉路徑
context.restore();//恢復之前保存的繪制狀態
//繪制時鐘上表示小時的文字
var r = radius - 10;//縮小半徑，因為要將文字繪制在時鐘內部
context.font= 'bold 16px 宋體';//指定文字字體
Drawtext('1', centerx + (0.5 * r), centery - (0.88 * r));
Drawtext('2', centerx + (0.866 * r), centery - (0.5 * r));
Drawtext('3', centerx + radius - 10,centery);
Drawtext('4', centerx + (0.866 * r), centery + (0.5 * r));
Drawtext('5', centerx + (0.5 * r), centery + (0.866 * r));
Drawtext('6', centerx, centery + r);
Drawtext('7', centerx - (0.5 * r), centery + (0.866 * r));
Drawtext('8', centerx - (0.866 * r), centery + (0.49 * r));
Drawtext('9', centerx - radius + 10, centery);
Drawtext('10',centerx - (0.866 * r),centery - (0.50 * r));
Drawtext('11', centerx - (0.51 * r), centery - (0.88 * r));
Drawtext('12', centerx, 35);
//繪制時鐘指針
var date=new Date();//獲取需要表示的時間
var h = date.getHours();//獲取當前小時
var m = date.getMinutes();//獲取當前分鐘
var s=date.getSeconds();//獲取當前秒
var a = ((h/12) *Math.PI*2) - 1.57 + ((m / 60) * 0.524);//根據當前時間計算指針角度
context.save();//保存當前繪制狀態
context.fillStyle='black'; //指定指針中心點的顏色
context.beginPath();//開始創建路徑
context.arc(centerx,centery,3,0,Math.PI * 2, 0);//創建指針中心點的路徑
context.closePath();//關閉路徑
context.fill();//填充指針中心點
context.lineWidth=3;//指定指針寬度
context.fillStyle='darkgray';//指定指針填充顏色
context.strokeStyle='darkgray';//指定指針邊框顏色
context.beginPath();//開始創建路徑
//繪制小時指針
context.arc(centerx,centery,radius - 55, a + 0.01, a, 1);
context.lineTo(centerx,centery);
//繪制分鐘指針
context.arc(centerx,centery,radius - 40, ((m/60) * 6.27) - 1.57, ((m/60) * 6.28) - 1.57, 0);
context.lineTo(canvas.width / 2, canvas.height / 2);
//繪制秒鐘指針
context.arc(centerx,centery,radius - 30, ((s/60) * 6.27) - 1.57, ((s/60) * 6.28) - 1.57, 0);
context.lineTo(centerx,centery);
context.closePath();//關閉路徑
context.fill();//填充指針
context.stroke();//繪制指針邊框
context.restore();//恢復之前保存的繪制狀態
//指定時鐘下部當前時間所用的字符串，文字格式為hh:mm:dd
var hours = String(h);
var minutes = String(m);
var seconds = String(s);
if (hours.length == 1) h = '0' + h;
if (minutes.length == 1) m = '0' + m;
if (seconds.length == 1) s = '0' + s;
var str =h + ':' + m + ':' +s;
//繪制時鐘下部的當前時間
Drawtext(str, centerx, centery + radius + 12);
}
function Drawtext(text, x, y)
{
//因為需要使用到坐標平移，所以在平移前線保存當前繪制狀態
context.save();
x -= (context.measureText(text).width / 2);//文字起點橫坐標
y +=9;//文字起點縱坐標
context.beginPath();//開始創建路徑
context.translate(x, y);//平移坐標
context.fillText(text,0,0);//填充文字
context.restore();
}
</script>
<style>
div{
display: -moz-box;
display: -webkit-box;
-moz-box-pack: center;
-webkit-box-pack: center;
width:100%;
}
canvas{
background-color:white;
}
</style>
</head>
<body onload="window_onload()">
<div><h1>使用canvas元素繪制指針式動畫時鐘</h1></div>
<div><canvas id="canvas" width="200px" height="200px"></canvas><div>//這裏就是妳的時鐘的位置。
</body>
</html>