css3+js绘制动态时钟（附代码）
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本章给大家介绍如何使用css3与js实现动态时钟效果，有一定的参考价值，有需要的朋友可以参考一下，希望对你有所帮助。
先看看效果图：
首先,思考了一下页面的布局,大致需要4层div,最底层是一个表盘的背景图,然后其余3层分别是时针,分针,秒针的图层.
html代码如下：
<div class="dial">
</div>
<div class="bigdiv bigdiv1" id="secondHand">
<div class="secondHand"></div>
</div>
<div class="bigdiv bigdiv2" id="minuteHand">
<div class="minuteHand"></div>
</div>
<div class="bigdiv bigdiv3" id="hourHand">
<div class="center"></div>
<div class="hourHand"></div>
</div>变量名是随便起的,不要介意; class=center的这个div是表中心那个小黑点.
时针是60*60*60s转一圈, 分针是60*60s转一圈, 秒针是60s转一圈, 所以css代码如下：
.dial{
width:600px;
height:600px;
margin:0 auto;
position: absolute;
border-radius: 50%;
overflow: hidden;
background-color: rgba(153,50,204,0.2);
background-image: url(img/表盘.jpg);
background-size: 100% 100%;
}
.bigdiv{
width:600px;
height:600px;
margin:0 auto;
position: absolute;
border-radius: 50%;
overflow: hidden;
}
.bigdiv>div{
position: absolute;
left:298px;
border-radius: 100px;
}
.bigdiv1{
animation: moves 60s steps(60) infinite;
}
.bigdiv1 .secondHand{
width:4px;
height:250px;
background-color: red;
top:50px;
left:298px;
}
.bigdiv2{
animation: moves 3600s steps(3600) infinite;
}
.bigdiv2 .minuteHand{
width:6px;
height:180px;
background-color: green;
top:120px;
left:297px;
}
.bigdiv3{
animation: moves 216000s steps(216000) infinite;
}
.bigdiv3 .hourHand{
width:8px;
height:160px;
background-color: orange;
top:140px;
left:296px;
border-radius: 100px;
}
.bigdiv .center{
top:290px;
left:290px;
width:20px;
height:20px;
background-color: black;
z-index: 2;
}
@keyframes moves{
from{ transform: rotateZ(0deg); }
to{ transform: rotateZ(360deg); }
}这一步做完后效果图是这个样子的:
然后用js计算当前时间,
var date = new Date();
var hours = date.getHours();
var minutes = date.getMinutes();
var seconds = date.getSeconds();然后计算当前每个针的旋转角度
var secondAngle = seconds;
var minuteAngle = minutes * 60 + seconds;
var hourAngle = (60/12) * ((hours%12) * 3600 + minuteAngle);现在的思路就是:每个针会按照自己定的时间转一圈,初始角度也能知道,怎么组成一个显示当前时间的动态钟表呢?
刚开始的想法是让这3层div旋转对应的角度,然后再开始,后来一想不行,因为它还是固定的时间旋转一周,指针指向会有偏差,
现在需要的是页面进来的第一圈旋转固定角度,其余的按照原来固定的时间旋转一周就行了,
css3里面有一个animation-delay属性,它表示的意思是动画延迟,负数就表示提前开始(比如-5s就表示动画从第5s的时间开始),
刚好可以用到,让这几个指针提前开始对应的角度.
js代码如下：
hourHand.style.cssText = "animation-delay: -"+ hourAngle +"s";
minuteHand.style.cssText = "animation-delay: -"+ minuteAngle +"s";
secondHand.style.cssText = "animation-delay: -"+ secondAngle +"s";最后自己再加了个动态时间在钟表的上面展示
完整代码：
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title></title>
<style>
body,
html {
margin: 0;
}
.location {
position: relative;
width: 600px;
height: 600px;
left: calc(50% - 300px);
}
.dial {
width: 600px;
height: 600px;
margin: 0 auto;
position: absolute;
border-radius: 50%;
overflow: hidden;
background-color: rgba(153, 50, 204, 0.2);
background-image: url(img/表盘.jpg);
background-size: 100% 100%;
}
.bigdiv {
width: 600px;
height: 600px;
margin: 0 auto;
position: absolute;
border-radius: 50%;
overflow: hidden;
}
.bigdiv>div {
position: absolute;
left: 298px;
border-radius: 100px;
}
.bigdiv1 {
animation: moves 60s steps(60) infinite;
}
.bigdiv1 .secondHand {
width: 4px;
height: 250px;
background-color: red;
top: 50px;
left: 298px;
}
.bigdiv2 {
animation: moves 3600s steps(3600) infinite;
}
.bigdiv2 .minuteHand {
width: 6px;
height: 180px;
background-color: green;
top: 120px;
left: 297px;
}
.bigdiv3 {
animation: moves 216000s steps(216000) infinite;
}
.bigdiv3 .hourHand {
width: 8px;
height: 160px;
background-color: orange;
top: 140px;
left: 296px;
border-radius: 100px;
}
.bigdiv .center {
top: 290px;
left: 290px;
width: 20px;
height: 20px;
background-color: black;
z-index: 2;
}
@keyframes moves {
from {
transform: rotateZ(0deg);
}
to {
transform: rotateZ(360deg);
}
}
#dateshow {
text-align: center;
}
</style>
</head>
<body>
<h1 id="dateshow"></h1>
<div class="location">
<div class="dial"></div>
<div class="bigdiv bigdiv1" id="secondHand">
<div class="secondHand"></div>
</div>
<div class="bigdiv bigdiv2" id="minuteHand">
<div class="minuteHand"></div>
</div>
<div class="bigdiv bigdiv3" id="hourHand">
<div class="center"></div>
<div class="hourHand"></div>
</div>
</div>
<script>
var dateshow = document.getElementById("dateshow");
var clock = {
weeks: ["一", "二", "三", "四", "五", "六", "日"],
getDate: function() {
date = new Date();
year = date.getFullYear();
month = date.getMonth() + 1;
day = date.getDate();
hours = date.getHours();
minutes = date.getMinutes();
seconds = date.getSeconds();
week = date.getDay(); // 星期
dateText = year + "年" + month + "月" + clock.format(day) + "日 星期" + clock.formatnum(week) + " " +
clock.format(hours) + ":" + clock.format(minutes) + ":" + clock.format(seconds);
return dateText;
},
format: function(data) {
if(data.toString().length == 1) {
data = "0" + data;
};
return data;
},
formatnum: function(num) {
return clock.weeks[num - 1];
},
showdate: function() {
dateshow.innerText = clock.getDate();
},
go: function() {
var secondHand = document.getElementById("secondHand");
var minuteHand = document.getElementById("minuteHand");
var hourHand = document.getElementById("hourHand");
date = new Date();
hours = date.getHours();
minutes = date.getMinutes();
seconds = date.getSeconds();
var secondAngle = seconds;
var minuteAngle = minutes * 60 + seconds;
var hourAngle = (60 / 12) * ((hours % 12) * 3600 + minuteAngle);
hourHand.style.cssText = "animation-delay: -" + hourAngle + "s";
minuteHand.style.cssText = "animation-delay: -" + minuteAngle + "s";
secondHand.style.cssText = "animation-delay: -" + secondAngle + "s";
}
}
clock.go();
clock.showdate();
setInterval("clock.showdate()", 1000);
</script>
</body>
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