代码:
javascript
<!DOCTYPE html>
<html lang="zh-CN">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>警灯效果红蓝闪烁</title>
<style>
/* 调整元素的明暗 */
/* filter: brightness(100%); */
.context{
margin-left: 150px;
}
.red{
float: left;
width: 50px;
height: 100px;
background-color: red;
border: 50px solid red;
border-top-left-radius: 50px;
border-top-right-radius: 50px;
opacity: 0.5;
}
.blue{
float: left;
width: 50px;
height: 100px;
background-color: blue;
border: 50px solid blue;
border-top-left-radius: 50px;
border-top-right-radius: 50px;
opacity: 0.5;
}
</style>
</head>
<body>
<div class="context">
<div class="red">
</div>
<div class="blue">
</div>
</div>
<script>
let redlamp = document.getElementsByClassName('red')[0]
let bluelamp = document.getElementsByClassName('blue')[0]
let i=0
setInterval(o=>{
if(i%2==0){
redlamp.style.opacity='1'
bluelamp.style.opacity='0.5'
i++
}else{
redlamp.style.opacity='0.5'
bluelamp.style.opacity='1'
i++
}
},300)
</script>
</body>
</html>
效果图: