<!DOCTYPE html> <html lang="en"> <head> <meta charset="utf-8"> <title></title> <script src="../../jquery-3.2.1.min.js"></script> <style type="text/css"> *{margin: 0;padding:0;} body{height:1500px;} .context{width:100%;height:50px;background:rgba(150,150,150,0.5); box-shadow:1px 2px 7px #ccc;position:fixed;} .context form{width:600px;height:50px;background:rgba(100,100,100,0.5);margin:0 auto;line-height:50px;position:relative;} .context form input{width:500px;height:30px;line-height:30px;margin:0 auto; border-top-left-radius:20px;border-bottom-left-radius:20px;border:none; padding-left:20px; outline:none;} .context form button{width:100px;height:30px;line-height:30px;border-top-right-radius:20px; border-bottom-right-radius:20px;border:none;text-align:center; position:absolute;right:0px;top:11px; } .pic{width:50%;height:400px;background-image:url(images/3.jpg); margin:0 auto;} .context1{background:rgba(160,3,162,0.4);} </style> </head> <body> <div class="context"> <form> <input type="text" placeholder="#请输入此处#"> <button>全网搜</button> </form> </div> <div class="pic"></div> <div class="box"></div> </body> <script> $(function(){ $(window).scroll( function(){ if($(window).scrollTop()>60){ $('.context').css('display','none'); }else{ $('.context').css('display','block'); } if($(window).scrollTop()>350){ $('.context').css('display','block'); $('.context').addClass('context1'); }else{ $('.context').removeClass('context1'); } }) }) </script> </html>
点击 "运行实例" 按钮查看在线实例