javascript中返回顶部按钮的实现

炫酷的返回顶部功能

js核心代码

= 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

rush:xhtml;">

display: none; float: left; position: fixed; margin-left: 50%; cursor: pointer; margin-bottom: 20px;" id="flypig">

display: none; float: left; position: fixed; bottom: 10px; margin-left: 50%; cursor: pointer;" id="go" onclick="pageScroll()">返回顶部

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