炫酷的返回顶部功能

js核心代码

window.onscroll = function(){ 
  var t = document.documentElement.scrollTop || document.body.scrollTop; 
  var top_div = document.getElementById( "go" ); 
  if( t >= 300 ) { 
    top_div.style.display = "block"; 
  } else { 
    top_div.style.display = "none"; 
  } 
} 
 
 
var ptt=20;
function pageScroll() {
 
document.getElementById('flypig').style.display='block';
window.scrollBy(0,-10); //每次上升10px
 
 
 
if(document.body.scrollTop==0) {  
  document.getElementById('flypig').style.marginBottom=ptt+'px';
  ptt=ptt+10; 
}
scrolldelay = setTimeout('pageScroll()',2); //2毫秒重复执行一次
 
if(ptt>=1000){
  ptt=0;
  document.getElementById('flypig').style.marginBottom=20+'px';
  document.getElementById('flypig').style.display='none';
  clearTimeout(scrolldelay);
}
//pageScroll ends
} 
    

html

 
 

body{
  margin:0px;
}
#flypig{
 display: none; 
 float: left; 
 position: fixed; 
 bottom: 20px; 
 margin-left: 75%; 
 cursor: pointer; 
 margin-bottom: 20px;
}
#go{
 display: block; 
 float: left; 
 position: fixed; 
 bottom: 10px; 
 margin-left: 75%; 
 cursor: pointer;
}
































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返回顶部

以上所述就是本文的全部内容了，希望大家能够喜欢。