js返回顶部的通用方法
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<!DOCTYPE html> <html> <head> <meta charset="UTF-8"> <title></title> <script type="text/javascript"> function backTop(btnId) { var btn = document.getElementById(btnId); var d = document.documentElement; var b = document.body; window.onscroll = set; btn.style.display = "none"; btn.onclick = function() { btn.style.display = "none"; window.onscroll = null; this.timer = setInterval(function() { d.scrollTop -= Math.ceil((d.scrollTop + b.scrollTop) * 0.1); b.scrollTop -= Math.ceil((d.scrollTop + b.scrollTop) * 0.1); if ((d.scrollTop + b.scrollTop) == 0) clearInterval(btn.timer, window.onscroll = set); }, 10); }; function set() { btn.style.display = (d.scrollTop + b.scrollTop > 100) ? 'block': "none" } }; </script> </head> <body> <br> <br> <br> <br> <br> <br> <br> <br> <br> <br> <br> <br> <br> <br> <br> <br> <br> <br> <br> <br> <br> <br> <br> <br> <br> <br> <br> <br> <br> <br> <br> <br> <br> <br> <br> <br> <br> <br> <br> <br> <br> <br> <br> <br> <a href="#" id='goTop' onclick="backTop('goTop');">顶部</a> </body> </html> |
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