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javascript Back to Top Effects

  • 2021-07-06 10:04:38
  • OfStack

The example of this article shares the effect of javascript returning to the top for your reference. The specific contents are as follows 


<!DOCTYPE html>
<html lang="en">
<head>
 <meta charset="UTF-8">
 <meta http-equiv="X-UA-Compatible" content="IE=Edge,chrome=1">
 <title> Back to Top Effect (Native 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/ Web page top Small icon (back to the top) / Back to the top -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 Structure oScroll Function 
 function oScroll(){
  var osTop=document.documentElement.scrollTop||document.body.scrollTop;//1.1 Rolling height , Compatible 
  var oSpeed=Math.ceil(osTop/4);// Rolling speed 
  document.documentElement.scrollTop=document.body.scrollTop=osTop-oSpeed;
  if(osTop==0){// Judge to reach the top , Cleaning timer 
   clearInterval(timer);
  }
  isScroll=true; 
 }
      
 window.onload=function() {
  var obtn=document.getElementById('btn');// Get button element 
  var clientHeight=document.documentElement.clientHeight||document.body.clientHeight;

  // 1. Click the Back button event  
  btn.onclick=function(){// Bind click events to buttons 
   timer=setInterval(oScroll,50); 
  } 
  window.onscroll=function() {
   var osTop=document.documentElement.scrollTop||document.body.scrollTop;//1.1 Rolling height , Compatible 
   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=" Back to the top " id="btn" class="btn"> Back to the top </a>
</body>
</html>

The above is the whole content of this article, hoping to help everyone learn JavaScript programming.

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