javascript回到顶部特效

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我是靠谱客的博主彪壮火车，这篇文章主要介绍javascript回到顶部特效，现在分享给大家，希望可以做个参考。

本文实例为大家分享了javascript回到顶部效果，供大家参考，具体内容如下

复制代码

<!DOCTYPE html>
<html lang="en">
<head>
 <meta charset="UTF-8">
 <meta http-equiv="X-UA-Compatible" content="IE=Edge,chrome=1">
 <title>回到顶部效果（原生js）</title>
 <style type="text/css">
  body{
   margin: 0;

}
  .bg{
   width: 1022px;
   margin: 0 auto;
  }
  .btn{
   display: none;
   width: 75px;
   height: 75px;
   background:url(../images/网页top小图标（返回顶部）/返回顶部-085.png) no-repeat left top;
   position: fixed;
   left: 50%;
   margin-left: 530px;
   bottom: 10px;
   text-indent: -9999px;
   outline: none;
  }
  .btn:hover{
   background-position: 0 -75px;
  }
 </style>
 
 <script>  
 var timer=null;
 var isScroll=true;
 //1.2构造oScroll函数
 function oScroll(){
  var osTop=document.documentElement.scrollTop||document.body.scrollTop;//1.1滚动高度,兼容
  var oSpeed=Math.ceil(osTop/4);//滚动速度
  document.documentElement.scrollTop=document.body.scrollTop=osTop-oSpeed;
  if(osTop==0){//判断到达顶部,清理定时器
   clearInterval(timer);
  }
  isScroll=true; 
 }
      
 window.onload=function() {
  var obtn=document.getElementById('btn');//获取按钮元素
  var clientHeight=document.documentElement.clientHeight||document.body.clientHeight;

// 1.点击返回按钮事件 
  btn.onclick=function(){//为按钮绑定点击事件
   timer=setInterval(oScroll,50); 
  } 
  window.onscroll=function() {
   var osTop=document.documentElement.scrollTop||document.body.scrollTop;//1.1滚动高度,兼容
   if (osTop>clientHeight) {
    btn.style.display="block";
   }else{
    btn.style.display="none";
   }
   if(!isScroll){
    clearInterval(timer);
   }
   isScroll=false;
  }
 }

</script>

</head>
<body>
 <div class="bg">
  <img src="../images/jz.jpg">
 </div>
 <a href="javascript：void(0);" title="返回顶部" id="btn" class="btn">返回顶部</a>
</body>
</html>

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<!DOCTYPE html>
<html lang="en">
<head>
 <meta charset="UTF-8">
 <meta http-equiv="X-UA-Compatible" content="IE=Edge,chrome=1">
 <title>回到顶部效果（原生js）</title>
 <style type="text/css">
  body{
   margin: 0;

  }
  .bg{
   width: 1022px;
   margin: 0 auto;
  }
  .btn{
   display: none;
   width: 75px;
   height: 75px;
   background:url(../images/网页top小图标（返回顶部）/返回顶部-085.png) no-repeat left top;
   position: fixed;
   left: 50%;
   margin-left: 530px;
   bottom: 10px;
   text-indent: -9999px;
   outline: none;
  }
  .btn:hover{
   background-position: 0 -75px;
  }
 </style>
 
 <script>  
 var timer=null;
 var isScroll=true;
 //1.2构造oScroll函数
 function oScroll(){
  var osTop=document.documentElement.scrollTop||document.body.scrollTop;//1.1滚动高度,兼容
  var oSpeed=Math.ceil(osTop/4);//滚动速度
  document.documentElement.scrollTop=document.body.scrollTop=osTop-oSpeed;
  if(osTop==0){//判断到达顶部,清理定时器
   clearInterval(timer);
  }
  isScroll=true; 
 }
      
 window.onload=function() {
  var obtn=document.getElementById('btn');//获取按钮元素
  var clientHeight=document.documentElement.clientHeight||document.body.clientHeight;

  // 1.点击返回按钮事件 
  btn.onclick=function(){//为按钮绑定点击事件
   timer=setInterval(oScroll,50); 
  } 
  window.onscroll=function() {
   var osTop=document.documentElement.scrollTop||document.body.scrollTop;//1.1滚动高度,兼容
   if (osTop>clientHeight) {
    btn.style.display="block";
   }else{
    btn.style.display="none";
   }
   if(!isScroll){
    clearInterval(timer);
   }
   isScroll=false;
  }
 } 


 </script>

</head>
<body>
 <div class="bg">
  <img src="../images/jz.jpg">
 </div>
 <a href="javascript：void(0);" title="返回顶部" id="btn" class="btn">返回顶部</a>
</body>
</html>