【梅花二度】js+css实现全屏侧边栏

在浏览网站时我们经常会看到一个菜单按钮，点一下就会出现一栏侧边导航栏代码HTML部分<div id="mySidenav" class="sidenav"> <a href="javascript:void(0)" class="closebtn" onclick="closeNav()">×</a> <a href="#">About</a> <a href="#">Services</a> <a href="#">Clients</a> <a href="#">Contact</a> </div> <h2>全屏幕侧边栏</h2> <p>点击以下菜单图标打开侧边栏</p> <span style="font-size:30px;cursor:pointer" onclick="openNav()">? 打开</span>


css部分body { font-family: "Lato", sans-serif; } .sidenav { height: 100%;width: 0;position: fixed;z-index: 1;  top: 0; left: 0; background-color: #111; overflow-x: hidden;  transition: 0.5s;  padding-top: 60px; text-align:center; } .sidenav a {  padding: 8px 8px 8px 32px; text-decoration: none; font-size: 25px;color: #818181; display: block; transition: 0.3s;  }  .sidenav a:hover{ color: #f1f1f1;  }  .sidenav .closebtn {position: absolute; top: 0; right: 25px; font-size: 36px; margin-left: 50px;  }  @media screen and (max-height: 450px)   { .sidenav {padding-top: 15px;  }   .sidenav a {font-size: 18px;  }  }JavaScript部分function openNav() {document.getElementById("mySidenav").style.width = "100%";}function closeNav() {document.getElementById("mySidenav").style.width = "0";}