js实现星星海特效的示例

时间:2020-09-28 君莫笑丶丶人气:0

本文着重讲解了js实现星星海特效的示例，帮助大家制作网页特效，欢迎大家阅读

首先需要获取屏幕大小：

 var screenWidth = document.documentElement.clientWidth;
 var screenHeight = document.documentElement.clientHeight;

接着可以定义动画（星星透明度）：

@keyframes flash {
   0%{opacity: 0}
   25%{opacity: 0.25}
   50%{opacity: 0.5}
   75%{opacity: 0.75}
   100%{opacity: 1}
  }

全部代码如下：

<!DOCTYPE html>
<html lang="en">
<head>
 <meta charset="UTF-8">
 <title>Title</title>
 <style>
  div{
   width: 70px;
   height: 80px;
   background: url("./images/star.jpg") no-repeat;
   animation: flash 1s;
  }
  body{
   background-color: black
  }
  @keyframes flash {
   0%{opacity: 0}
   25%{opacity: 0.25}
   50%{opacity: 0.5}
   75%{opacity: 0.75}
   100%{opacity: 1}
  }
 </style>
</head>
<body>

<script>
 var screenWidth = document.documentElement.clientWidth;
 var screenHeight = document.documentElement.clientHeight;
 // 生产50个星星
 for (let i = 0; i <50 ; i++) {
  var box=document.createElement('div');
  document.body.appendChild(box);
  x=Math.random()*screenWidth;
  y=Math.random()*screenHeight;
  box.style.position='relative';
  box.style.left=x+'px';
  box.style.right=y+'px';
 }
 boxList=document.getElementsByTagName("div");
 for (let i = 0; i < boxList.length; i++) {
  boxList[i].onmouseover=function () {
   this.style.transform='scale(1.5,1.5)';
  };
  boxList[i].onmouseout=function () {
   this.style.transform='scale(1,1)';
  };
 }
</script>
</body>
</html>

效果如下：

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