1 <html> 2 <head> 3 <style> 4 #myBtn { 5 display: none; 6 position: fixed; 7 bottom: 20px; 8 right: 30px; 9 z-index: 99; 10 border: none; 11 outline: none; 12 background-color: red; 13 color: white; 14 cursor: pointer; 15 padding: 15px; 16 border-radius: 10px; 17 } 18 19 #myBtn:hover { 20 background-color: #555; 21 } 22 </style> 23 </head> 24 <body> 25 26 <button onclick="topFunction()" id="myBtn" title="回顶部">返回顶部</button> 27 <script> 28 // 当网页向下滑动 20px 出现"返回顶部" 按钮 29 window.onscroll = function () { scrollFunction() }; 30 31 function scrollFunction() { 32 console.log(121); 33 if (document.body.scrollTop > 20 || document.documentElement.scrollTop > 20) { 34 document.getElementById("myBtn").style.display = "block"; 35 } else { 36 document.getElementById("myBtn").style.display = "none"; 37 } 38 } 39 40 // 点击按钮，返回顶部 41 function topFunction() { 42 document.body.scrollTop = 0; 43 document.documentElement.scrollTop = 0; 44 } 45 </script> 46 47 </body> 48 </html>
图片：
1 <html> 2 <head> 3 <style> 4 #myImg { 5 display: none; 6 position: fixed; 7 bottom: 20px; 8 right: 30px; 9 z-index: 99; 10 border: none; 11 outline: none; 12 cursor: pointer; 13 padding: 15px; 14 border-radius: 10px; 15 height: 100px; 16 } 17 18 #myImg:hover { 19 content: url('../../Resources/images/equip/置顶 1.png'); 20 } 21 </style> 22 </head> 23 <body> 24 25 <img onclick="topFunction()" id="myImg" title="回顶部" src="~/Resources/images/equip/置顶.png" /> 26 <script> 27 // 当网页向下滑动 20px 出现"返回顶部" 28 window.onscroll = function () { scrollFunction() }; 29 30 function scrollFunction() { 31 console.log(121); 32 if (document.body.scrollTop > 20 || document.documentElement.scrollTop > 20) { 33 document.getElementById("myImg").style.display = "block"; 34 } else { 35 document.getElementById("myImg").style.display = "none"; 36 } 37 } 38 39 // 点击按钮，返回顶部 40 function topFunction() { 41 document.body.scrollTop = 0; 42 document.documentElement.scrollTop = 0; 43 } 44 </script> 45 46 </body> 47 </html>