点击链接scrollTop滚动条移动

<!DOCTYPE html>
<html>
   <head>
       <meta charset="UTF-8">
       <title></title>
       <style type="text/css">
       *{    margin: 0; }
           ul{   width: 100%;height: 30px;position: fixed;display: none;}
           ul li{float: left;list-style: none;width: 250px;height: 30px;
               text-align: center;font-family: "微软雅黑";font-size: 20px;
               color: white;}
           div{width: 100%;
               height: 500px;
               text-align: center;
               font-size: 50px;
               line-height: 500px;
           }
           #btn{
               position: fixed;
               right: 0;
               bottom: 0;
               height: 50px;
               font-family: "微软雅黑";
               font-size: 18px;
               display: none;
           }
       </style>
   </head>
   <body>
       <ul id="ul1">
           <li style="background-color: red;" class="li1">1</li>
           <li style="background-color: black;" class="li1">2</li>
           <li style="background-color: blue;" class="li1">3</li>
           <li style="background-color: pink;" class="li1">4</li>
           <li style="background-color: green;" class="li1">5</li>
       </ul>
       <div class="diva" style="background:red;">红色区域</div>
       <div class="diva" style="background:black;">黑色区域</div>
       <div class="diva" style="background:blue;">蓝色区域</div>
       <div class="diva" style="background:pink;">粉色区域</div>
       <div class="diva" style="background:green;">绿色区域</div>
       <button id="btn">返回顶部</button>
       <script>
       /*
       原理：
       每次点击li时让li的高度值等于每个对应的div的scrollTop值
       * */
       window.onscroll = function (){
           var oUl = document.getElementById('ul1');
           var lis = document.getElementsByClassName('li1');
           var divs = document.getElementsByClassName('diva');
           var oBtn = document.getElementById('btn');
           var oScroll = document.documentElement.scrollTop||document.body.scrollTop;
           if(oScroll>200){
               oUl.style.display = 'block';
               oBtn.style.display = 'block';
           }else{
               oUl.style.display = 'none';
               oBtn.style.display = 'none';
           }
           oBtn.onclick = function (){
               document.documentElement.scrollTop = document.body.scrollTop = 0;
           }
           for (var i=0;i<lis.length;i++) {
               lis[i].index = i;//获取每一个li的索引下标
               lis[i].onclick = function (){
                   document.documentElement.scrollTop = document.body.scrollTop = (divs[this.index].offsetHeight)*this.index;
               }
           }
       }

       </script>
   </body>
</html>

点击链接scrollTop滚动条移动

猜你喜欢