<body>
<!--侧栏界面设计-->
<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>
<div id="main">
<h2>侧边栏实例 - 页面主体向右移动</h2>
<p>点击以下菜单图标打开侧边栏，主体内容向右2偏移。主体内容添加黑色透明背景</p>
<span style="font-size:30px;cursor:pointer" onclick="openNav()">☰ open</span>
</div>
</body>
<script type="text/javascript">
/*打开侧栏，修改侧栏宽度，主体左跨度、背景透明度*/
function openNav() {
document.getElementById("mySidenav").style.width = "250px";
document.getElementById("main").style.marginLeft = "250px";
document.body.style.backgroundColor = "rgba(0,0,0,0.4)";
}
/*关闭侧栏，恢复原始侧栏宽度，主体左跨度、背景透明度*/
function closeNav() {
document.getElementById("mySidenav").style.width = "0";
document.getElementById("main").style.marginLeft= "0";
document.body.style.backgroundColor = "white";
}
</script>
<style>
@charset "utf-8";
/* CSS Document */
body {
font-family: "Lato", sans-serif;
transition: background-color .5s;
}
/*侧边栏选择器*/
.sidenav {
height: 100%;
width: 0; /*原始宽度*/
position: fixed;
/*z-index、top、left共同控制侧栏的悬浮（上方1，下方-1）*/
z-index: 1;
top: 0;
left: 0;
background-color: #111;
overflow-x: hidden;
transition: 0.5s; /*侧栏延迟0.5s显示*/
padding-top: 60px;
}
/*侧边栏标签选择器*/
.sidenav a {
padding: 8px 8px 8px 32px;
text-decoration: none;
font-size: 25px;
color: #818181;
display: block;
transition: 0.3s; /*标签延迟0.3s显示*/
}
/*侧栏标签和关闭按钮光标的效果*/
.sidenav a:hover, .offcanvas a:focus{
color: #f1f1f1;
}
/*侧栏和关闭按钮的位置选择器*/
.sidenav .closebtn {
position: absolute;
top: 0;
right: 25px;
font-size: 36px;
margin-left: 50px;
}
/*主体内容*/
#main {
transition: margin-left .5s;/*主体内容延迟0.5s整体y右移动*/
padding: 16px;
}
/*当文档高度小于450px时，改变侧栏的padding属性和字体大小*/
@media screen and (max-height: 450px) {
.sidenav {padding-top: 15px;}
.sidenav a {font-size: 18px;}
}
</style>
