JS实现时钟效果

Posted 2021-02-17 baimeishaoxia

闲来无事，用JS写了个时钟，只要思路理清了，做起来其实还挺简单的。

先发个效果链接 点击查看

Demo

代码实现

HTML

<div id="warp" >
    <div id="clock" >
            <div id="number">
                <div><span>9</span></div>
                <div><span>10</span></div>
                <div><span>11</span></div>
                <div><span>12</span></div>
                <div><span>1</span></div>
                <div><span>2</span></div>
                <div><span>3</span></div>
                <div><span>4</span></div>
                <div><span>5</span></div>
                <div><span>6</span></div>
                <div><span>7</span></div>
                <div><span>8</span></div>
            </div>
            <div id="houre" class="pointer" ></div>
            <div id="minute" class="pointer" ></div>
            <div id="second" class="pointer" ></div>
    </div>
</div>

CSS

*{
    padding：0；
    margin：0；
}
html, body {
    height: 100%;
    background: #9c9;
}
#warp{
    width:230px;
    height:230px;
    margin:50px auto;
}
#clock{
    width:200px;
    height:200px;
    border-radius:115px;
    border:15px solid #f96;
    background:white;
    position:relative;
}
#number div{
    width:190px;
    height:20px;
    position:absolute;
    left:10px;
    top:90px;
}
#number span{
    display:block;
    width:20px;
    height:20px;
}
.pointer{
    position:absolute;
    bottom:90px;
    transform-origin:50% 90%;
    -webkit-transform-origin:50% 90%;
}
#houre{
    width:5px;
    height:60px;
    left:98px;
    background:black;
}
#minute{
    width:3px;
    height:70px;
    left:99px;
    background:gray;
}
#second{
    width:1px;
    height:80px;
    left:100px;
    background:red;
}

这里要注意的是number里面div的宽度给够，要不然后面用JS布局会出现问题。

JavaScript

var oNumber=document.getElementById("number");
var oDiv=oNumber.getElementsByTagName("div");
var oSpan=oNumber.getElementsByTagName("span");
for(var i=0;i<oDiv.length;i++){
    oDiv[i].style.WebkitTransform="rotate(" + i * 30 + "deg)";
}    
for(var j=0;j<oSpan.length;j++){
    oSpan[j].style.WebkitTransform="rotate("+ j * -30 + "deg)";
}    
function ColorNumber(){
    var oHoure=document.getElementById("houre");
    var oMinute=document.getElementById("minute");
    var oSecond=document.getElementById("second");

    var nowTime=new Date();
    var nowHoure=nowTime.getHours();
    var nowMinute=nowTime.getMinutes();
    var nowSecond=nowTime.getSeconds();
    var houreDeg=(nowMinute/60)*30;
    var minuteDeg=(nowSecond/60)*6;
    oHoure.style.WebkitTransform="rotate("+ (nowHoure * 30+houreDeg) + "deg)";
    oMinute.style.WebkitTransform="rotate("+ (nowMinute * 6+ minuteDeg) + "deg)";
    oSecond.style.WebkitTransform="rotate("+ (nowSecond * 6) + "deg)";
}
ColorNumber();
setInterval(ColorNumber,1000);

这里主要代码就两段，一段是布局用的，让数字旋转到相应的位置并调整方向：

for(var i=0;i<oDiv.length;i++){
    oDiv[i].style.WebkitTransform="rotate(" + i * 30 + "deg)";
}    
for(var j=0;j<oSpan.length;j++){
    oSpan[j].style.WebkitTransform="rotate("+ j * -30 + "deg)";
}

另一段是计算指针的角度，其中最重要的是在不满一小时或不满一分钟时，时针或分针应该转多少度：

var houreDeg=(nowMinute/60)*30;
var minuteDeg=(nowSecond/60)*6;

It‘s done.是不是很简单......