一、简介响应式下拉菜单可在多个移动端显示会有不同的效果。二、代码如下<!doctype html><html> <head> <meta charset="utf-8"/> <meta name="viewport" content="width=device-width"/> <title>响应式下拉菜单</title> <link rel="stylesheet" type="text/css" href="demo020.css" media="screen and (min-width:1024px)"/> <link rel="stylesheet" type="text/css" href="demo021.css" media="screen and (max-width:1024px)"/> <link href="https://cdn.bootcss.com/font-awesome/4.7.0/css/font-awesome.css" rel="stylesheet"> </head> <body> <div class="nav"> <div class="toggle"> <img class="tu" src="shitu2.png"/> <i id="btn" class="fa fa-bars"></i> </div> <div class="bb"></div> <ul id="menu" class="clearfix"> <li><a href="#">First</a></li> <li><a href="#">Second</a></li> <li><a href="#">Third</a></li> <li><a href="#">Fourth</a></li> <li><a href="#">Fifth</a></li> </ul> </div> <script type="text/javascript"> var btn=document.getElementById("btn"); var menu=document.getElementById("menu"); btn.onclick=function(){ //alert(1); if(menu.style.display=="none"){ menu.style.display="block"; }else{ menu.style.display="none"; } } window.onresize=function(){ var vw=document.documentElement.clienWidth; if(vw>640){ menu.style.display="block"; } } </script> </body></html>body{margin:0;}.nav{width:100%;background-color:#00316b;position:relative;}ul{padding:0px;margin:0px;width:80%;margin:0 auto;background:#00316b;}ul>li{list-style:none;float:left;}ul>li>a{color:#fff;text-decoration:none;display:block;padding:20px 30px;}ul>li:hover{background-color:red;}.clearfix:after{display:block;content:"";height:0px;visibility:hidden;clear:both;}.clearfix{zoom:1;}.toggle{text-align:right;color:#fff;padding:20px;font-size:20px;background:black;/* background-color:#001r44; */display:none;overflow:hidden;}.tu{float:left;}.bb{position:absolute;background-image:url(shitu2.png);background-repeat:no-repeat;background-size:100px;width:100px;height:40px;left:20px;top:10px;}----------body{ margin:0;}.nav{ width:100%; background-color:#00316b;}ul{ padding:0px; margin:0px; width:100%; margin:0 auto; background:#00316b;}ul>li{ text-align:center; list-style:none; /* float:left; */}ul>li>a{ color:#fff; text-decoration:none; display:block; padding:20px 30px;}ul>li:hover{ background-color:red;}.clearfix:after{ display:block; content:""; height:0px; visibility:hidden; clear:both;}.clearfix{ zoom:1;}.toggle{ text-align:right; color:#fff; padding:20px; background:yellow; font-size:20px; overflow:hidden; display:block;}.tu{ float:left; width:100px;}第三、效果图如下这是视口大于1024px的时候所显示的内容<PC端>min-width:1024px这是视口小于1024px的时候所显示的内容<手机>max-width:1024px这是在手机上和iPad上的效果图
