1效果图
2 html
<!DOCTYPE html> <html> <head> <meta charset="UTF-8"> <meta name="viewport" content="width=device-width, initial-scale=1.0"> <meta http-equiv="X-UA-Compatible" content="ie=edge"> <title>测试页面</title> <script src="../js/lib/jquery-3.2.1.min.js"></script> <style> #ul{ list-style: none; background-color:darkgray; height:30px; width:100%; padding:0; position:fixed; margin-top:0; } #ul li{ height:30px; line-height:30px; width:100px; float:left; display:block; margin:auto; text-align: center; } #ul li:hover{ background-color:red; } </style> </head> <body> <ul id="ul"> <li>第一项</li> <li>第二项</li> <li>第三项</li> <li>第四项</li> <li>第五项</li> </ul> <div style="height:500px;" id="div1"></div> <div style="height:500px;" id="div2"></div> <div style="height:500px;" id="div3"></div> <div style="height:500px;" id="div4"></div> <div style="height:500px;" id="div5"></div> <script src="../js/test.js"></script> </body> </html>
3 jq
$(function(){ var length = $('#ul li').length; $(document).scroll(function(){ for(let i =0;i<length;i++){ let top = $('div').eq(i).offset().top;//获取当前元素离顶部的距离 let scrop = $(document).scrollTop();//获取页面滚动条离顶部的距离 console.log(scrop +' '+top); if(scrop>top){ $('#ul li').eq(i).css('color','red'); $('#ul li').eq(i).siblings().css('color',''); } } }) })