js 滚到页面顶部
Posted 哈姆PP
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一、滚到顶部,且滚动中,用户滚动鼠标无效
<style> .div1, .div2, .div3, .div4 { height: 400px; width: 400px; } .div1 { background: #eea7cf; } .div2 { background: #a95ee1; } .div3 { background: #c57cad; } .div4 { background: #790d86; } .fixed-tool { position: fixed; top: 50px; right: 0; display: none; /*border: 1px solid black;*/ } .fixed-tool > a { display: block; } .go-top { background: #bb9cff; padding: 10px 1px; } .go-top-with-img { padding: 0; width: 40px; height: 40px; background: url(top_bg.png) no-repeat; } .go-top-with-img:hover { background-position: left -40px; } </style> </head> <body> <h1 id="title1">标题1 </h1> <div class="div1"></div> <h1>标题2</h1> <div class="div2"></div> <h1>标题3</h1> <div class="div3"></div> <h1>标题4 </h1> <div class="div4"></div> <h1>标题5 </h1> <div class="div1"></div> <h1>标题6 </h1> <div class="div3"></div> <h1>标题7</h1> <div class="div2"></div> <h1>标题8 </h1> <br/> <div class="fixed-tool" id="fixedTool"> <a href="#title1">标题1</a> <a href="javascript:;" class="go-top">顶部</a> <a href="javascript:;" class="go-top-with-img" id="goTop"></a> </div> <script> //"use strict"; window.onload = function () { var oGoTopLink = document.getElementById("goTop"); var iClientHeight = document.documentElement.clientHeight; var fixedTool = document.getElementById("fixedTool"); var timer = null; window.onscroll = function () { //判断是否滚到了第二屏,是则显示,否则隐藏 var sScrollTop = document.body.scrollTop || document.documentElement.scrollTop; if (sScrollTop >= iClientHeight) { fixedTool.style.display = "block"; } else { fixedTool.style.display = "none"; } }; oGoTopLink.onclick = function () { timer = setInterval(function () { var sScrollTop = document.body.scrollTop || document.documentElement.scrollTop; var iSpeed = Math.floor(-sScrollTop / 12); document.body.scrollTop = document.documentElement.scrollTop = sScrollTop + iSpeed; document.body.onmousewheel = function(){ return false; }; if (sScrollTop <= 0) { clearInterval(timer); document.body.onmousewheel = function(){ return true; }; } }, 30); } }; </script> </body> </html>
封装此方法:
//封装以上方法: /** * @param {String} sWrapId :the element which wraped the go-to-top link * @param {String} sEleId :the go-to-top element * @param {Number} iSpeed : speed of scrolling ,smaller faster * @returns {undefined} * usage: goTop("fixedTool", "goTop", 12); 关于样式:可以自己写,如果想用默认样式,就用我上述例子的那些class name, */ function goTop(sWrapId, sEleId, iSpeed){ var oGoTopLink = document.getElementById(sEleId); var iClientHeight = document.documentElement.clientHeight; var wrapBox = document.getElementById(sWrapId); var timer = null; window.onscroll = function () { //判断是否滚到了第二屏,是则显示,否则隐藏 var sScrollTop = document.body.scrollTop || document.documentElement.scrollTop; if (sScrollTop >= iClientHeight) { wrapBox.style.display = "block"; } else { wrapBox.style.display = "none"; } }; oGoTopLink.onclick = function () { timer = setInterval(function () { var sScrollTop = document.body.scrollTop || document.documentElement.scrollTop; var iScrollSpeed = Math.floor(-sScrollTop / iSpeed); document.body.scrollTop = document.documentElement.scrollTop = sScrollTop + iScrollSpeed; document.body.onmousewheel = function(){ return false; }; if (sScrollTop <= 0) { clearInterval(timer); document.body.onmousewheel = function(){ return true; }; } }, 30); }; return undefined; }
二,滚到顶部,且滚动中,若用户滚动鼠标,则停止滚到顶部动作
<script> //"use strict"; window.onload = function () { var oGoTopLink = document.getElementById("goTop"); var iClientHeight = document.documentElement.clientHeight; var fixedTool = document.getElementById("fixedTool"); var bIsTop = true; var timer = null; //当正在滚回顶部的动作中,用户滚动滚轮的话,停止滚回顶部的动作 window.onscroll = function () { //判断是否滚到了第二屏,是则显示,否则隐藏 var sScrollTop = document.body.scrollTop || document.documentElement.scrollTop; if (sScrollTop >= iClientHeight) { fixedTool.style.display = "block"; } else { fixedTool.style.display = "none"; } if (!bIsTop) { clearInterval(timer); } bIsTop = false; }; oGoTopLink.onclick = function () { timer = setInterval(function () { var sScrollTop = document.body.scrollTop || document.documentElement.scrollTop; var iSpeed = Math.floor(-sScrollTop / 12); document.body.scrollTop = document.documentElement.scrollTop = sScrollTop + iSpeed; bIsTop = true; if (sScrollTop <= 0) { clearInterval(timer); }, 30); } }; </script>
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