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javascript中返回頂部按鈕的實現(xiàn)

更新時間：2015年05月05日 11:24:24 投稿：hebedich

這篇文章主要介紹了使用javascript實現(xiàn)博客園頁面右下角返回頂部按鈕的思路及源碼,非常不錯,這里推薦給小伙伴們

炫酷的返回頂部功能

js核心代碼

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毫秒重復(fù)執(zhí)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

<!DOCTYPE html>
<html>
<head>
 <title>返回頂部按鈕的實現(xiàn)</title>
 <meta charset="utf-8" />
<style>
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;
}
</style>
<script>
 
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毫秒重復(fù)執(zhí)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
} 
    
</script>
</head>
<body>
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<h1 style="text-align:center;">請往下滑</h1>
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<br /><!--讓你的頁面足夠的長-->
<div style="display: none; float: left; position: fixed; margin-left: 50%; cursor: pointer; margin-bottom: 20px;" id="flypig">
<img src="/wp-content/themes/Jakesoft/images/flypig.gif">    </div>
<div style="display: none; float: left; position: fixed; bottom: 10px; margin-left: 50%; cursor: pointer;" id="go" onclick="pageScroll()">返回頂部</div></html>

以上所述就是本文的全部內(nèi)容了，希望大家能夠喜歡。

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