时钟效果图：
闲来无聊做了一个网页的时钟，效果模拟传统时钟的运行方式，
运用了html 的画布实现指针，背景图片引用了网络图片。
具体原理：
首先将时钟分为四个不同区域，对每个区域计算cos，sin 来确实指针顶点位置。在通过画布来绘画出指针。
通过setInterval 每秒刷新指针位置实现 传统机械表针的动态跳动。
本人是JS开发程序员，从业1年多。闲来无聊的简单页面，
欢迎大家提问，或者建议。共同进步
代码部分，直接复制HTML 文件中即可查看效果：
<!DOCTYPE html>
<html>
<head>
<meta charset=utf-8>
<title>clock</title>
</head>
<body style="color:green; <!--background-image:url('http://image.lxway.com/upload/b/f0/bf0d97dcee487096548e6edbc89d4963_thumb.png');--> background-size:100%; background-repeat: no-repeat; background-attachment:fixed">
<div style="width: 900px; height: 900px; margin-top: 50px; margin-left: 50px;">
<div style="position: absolute; left:119px;top: 193px; width: 900px; height: 900px; background-image:url('http://image.lxway.com/upload/b/f0/bf0d97dcee487096548e6edbc89d4963_thumb.png'); background-repeat: no-repeat; z-index: -1;">
</div>
<canvas id="t" width="800" height="800"></canvas>
<div style="position: absolute; left:118px;top: 464px; width: 100px; height: 200px; background-color: white; background-repeat: no-repeat; z-index: 10;">
</div>
</div>
<script language="javascript">
var s = setInterval(moveI, 1000);
function moveI() {
var c = document.getElementById("t");
var pc = c.getContext("2d");
c.height = c.height;
//秒
pc.lineWidth = 3;
pc.strokeStyle = 'rgba(255,0,0,0.8)';
var now = new Date();
var sindex = getxy(150, now.getSeconds());
pc.moveTo(400, 400);
pc.lineTo(sindex.x, sindex.y);
pc.stroke();
pc.beginPath();
//分
pc.lineWidth = 7;
pc.strokeStyle = 'rgba(50,50,50,0.8)';
var mindex = getxy(120, now.getMinutes() + (now.getSeconds() / 60));
pc.moveTo(400, 400);
pc.lineTo(mindex.x, mindex.y);
pc.stroke();
pc.beginPath();
//时
pc.lineWidth = 10;
pc.strokeStyle = 'rgba(0,0,0,0.8)';
var hindex = getxy(80, ((now.getHours() > 12 ? now.getHours() - 12 : now.getHours()) + (now.getMinutes() / 60)) * 5);
pc.moveTo(400, 400);
pc.lineTo(hindex.x, hindex.y);
pc.stroke();
};
function getxy(r, t) {
//计算分区 0,1,2,3
var a = parseInt(t / 15);
//分区角度
t = t - 15 * a;
var y;
var x;
//基于分区的坐标计算
switch (a) {
case 0:
y = r - (r * Math.cos(2 * Math.PI / 360 * 90 * (t / 15)));
x = r + (r * Math.sin(2 * Math.PI / 360 * 90 * (t / 15)));
break;
case 1:
y = r + (r * Math.sin(2 * Math.PI / 360 * 90 * (t / 15)));
x = r + (r * Math.cos(2 * Math.PI / 360 * 90 * (t / 15)));
break;
case 2:
y = r + (r * Math.cos(2 * Math.PI / 360 * 90 * (t / 15)));
x = r - (r * Math.sin(2 * Math.PI / 360 * 90 * (t / 15)));
break;
case 3:
y = r - (r * Math.sin(2 * Math.PI / 360 * 90 * (t / 15)));
x = r - (r * Math.cos(2 * Math.PI / 360 * 90 * (t / 15)));
break;
default:
break;
}
y = (400 - r) + y;
x = (400 - r) + x;
return {
'x': x,
'y': y
};
};
</script>
</body>
</html>
以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持。