position:static
忽略top/bottom/left/right或者z-index
position:relative
设置相对定位的元素不会脱离文档流
position:fixed
不会随着视口滚动而滚动，继承absolute的特点
position:sticky
和top属性搭配，可以设置吸附导航效果，但兼容性不太理想
专门建立的学习Q-q-u-n： 784783012 ，分享学习的方法和需要注意的小细节，不停更新最新的教程和学习技巧
（从零基础开始到前端项目实战教程，学习工具，全栈开发学习路线以及规划）
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>demo</title>
<style> *{margin:0;padding:0;} div{width:100%;} .banner{text-align: center;background-color:#f2f4f6;padding:100px 0;} .nav{text-align: center;border:1px solid #333;position: sticky;top:0;background-color:#abcdef;padding:20px 0;} .content{width:60%;margin:50px auto;} p{margin-bottom:50px;}
</style>
</head>
<body>
<div class="banner">这是广告图</div>
<div class="nav">导航 | 导航 | 导航</div>
<div class="content">
<p>position:sticky是css定位新增属性；可以说是相对定位relative和固定定位fixed的结合；它主要用在对scroll事件的监听上；简单来说，在滑动过程中，某个元素距离其父元素的距离达到sticky粘性定位的要求时(比如top：100px)；position:sticky这时的效果相当于fixed定位，固定到适当位置。</p>
<p>position:sticky是css定位新增属性；可以说是相对定位relative和固定定位fixed的结合；它主要用在对scroll事件的监听上；简单来说，在滑动过程中，某个元素距离其父元素的距离达到sticky粘性定位的要求时(比如top：100px)；position:sticky这时的效果相当于fixed定位，固定到适当位置。</p>
<p>position:sticky是css定位新增属性；可以说是相对定位relative和固定定位fixed的结合；它主要用在对scroll事件的监听上；简单来说，在滑动过程中，某个元素距离其父元素的距离达到sticky粘性定位的要求时(比如top：100px)；position:sticky这时的效果相当于fixed定位，固定到适当位置。</p>
<p>position:sticky是css定位新增属性；可以说是相对定位relative和固定定位fixed的结合；它主要用在对scroll事件的监听上；简单来说，在滑动过程中，某个元素距离其父元素的距离达到sticky粘性定位的要求时(比如top：100px)；position:sticky这时的效果相当于fixed定位，固定到适当位置。</p>
<p>position:sticky是css定位新增属性；可以说是相对定位relative和固定定位fixed的结合；它主要用在对scroll事件的监听上；简单来说，在滑动过程中，某个元素距离其父元素的距离达到sticky粘性定位的要求时(比如top：100px)；position:sticky这时的效果相当于fixed定位，固定到适当位置。</p>
<p>position:sticky是css定位新增属性；可以说是相对定位relative和固定定位fixed的结合；它主要用在对scroll事件的监听上；简单来说，在滑动过程中，某个元素距离其父元素的距离达到sticky粘性定位的要求时(比如top：100px)；position:sticky这时的效果相当于fixed定位，固定到适当位置。</p>
<p>position:sticky是css定位新增属性；可以说是相对定位relative和固定定位fixed的结合；它主要用在对scroll事件的监听上；简单来说，在滑动过程中，某个元素距离其父元素的距离达到sticky粘性定位的要求时(比如top：100px)；position:sticky这时的效果相当于fixed定位，固定到适当位置。</p>
</div>
</body>
</html>
左侧固定三级导航demo：
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>demo</title>
<style> *{margin:0;padding:0;} .page{width:100%;} .nav{position: fixed;top:50%;left:0;width:160px;height:205px;margin-top:-102.5px;} .nav-li{width:100%;/*height:40px;*/line-height:40px;text-align:center;color:#fff;background:#333;border-bottom:1px solid #fff;cursor: pointer;} .nav-li:hover ul{display: block;} .title{width:100%;height:40px;} .nav-li ul{width:100%;background-color: #fff;display: none;} .nav-li ul li{width:100%;height:40px;line-height:40px;text-align:center;color:#333;border-bottom:1px dashed #666;position: relative;} .nav-li ul li:hover .list3{display: block;} .list3{width:100%;position: absolute;top:0;left:160px;display: none;} .item3{width:100%;height:40px;line-height:40px;text-align:center;background:#444;color:#fff;border-bottom:1px dashed #666;}
</style>
</head>
<body>
<div class="page">
<div class="nav">
<div class="nav-li">
<div calss="title">一级导航1</div>
<ul>
<li>二级导航1 <div class="list3">
<div class="item3">三级导航1</div>
<div class="item3">三级导航2</div>
<div class="item3">三级导航3</div>
<div class="item3">三级导航4</div>
</div>
</li>
<li>二级导航2 <div class="list3">
<div class="item3">三级导航1</div>
<div class="item3">三级导航2</div>
<div class="item3">三级导航3</div>
<div class="item3">三级导航4</div>
</div>
</li>
<li>二级导航2 <div class="list3">
<div class="item3">三级导航1</div>
<div class="item3">三级导航2</div>
<div class="item3">三级导航3</div>
<div class="item3">三级导航4</div>
</div>
</li>
<li>二级导航2 <div class="list3">
<div class="item3">三级导航1</div>
<div class="item3">三级导航2</div>
<div class="item3">三级导航3</div>
<div class="item3">三级导航4</div>
</div>
</li>
</ul>
</div>
<div class="nav-li">
<div calss="title">一级导航1</div>
<ul>
<li>二级导航1 <div class="list3">
<div class="item3">三级导航1</div>
<div class="item3">三级导航2</div>
<div class="item3">三级导航3</div>
<div class="item3">三级导航4</div>
</div>
</li>
<li>二级导航2</li>
<li>二级导航3</li>
<li>二级导航4</li>
</ul>
</div>
<div class="nav-li">
<div calss="title">一级导航1</div>
<ul>
<li>二级导航1 <div class="list3">
<div class="item3">三级导航1</div>
<div class="item3">三级导航2</div>
<div class="item3">三级导航3</div>
<div class="item3">三级导航4</div>
</div>
</li>
<li>二级导航2</li>
<li>二级导航3</li>
<li>二级导航4</li>
</ul>
</div>
<div class="nav-li">
<div calss="title">一级导航1</div>
<ul>
<li>二级导航1 <div class="list3">
<div class="item3">三级导航1</div>
<div class="item3">三级导航2</div>
<div class="item3">三级导航3</div>
<div class="item3">三级导航4</div>
</div>
</li>
<li>二级导航2</li>
<li>二级导航3</li>
<li>二级导航4</li>
</ul>
</div>
<div class="nav-li">
<div calss="title">一级导航1</div>
<ul>
<li>二级导航1 <div class="list3">
<div class="item3">三级导航1</div>
<div class="item3">三级导航2</div>
<div class="item3">三级导航3</div>
<div class="item3">三级导航4</div>
</div>
</li>
<li>二级导航2</li>
<li>二级导航3</li>
<li>二级导航4</li>
</ul>
</div>
</div>
</div>
</body>
</html>
html+css网页项目布局demo:
专门建立的学习Q-q-u-n： 784783012 ，分享学习的方法和需要注意的小细节，不停更新最新的教程和学习技巧
（从零基础开始到前端项目实战教程，学习工具，全栈开发学习路线以及规划）
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>demo</title>
<style> *{margin:0;padding:0;} header{width:100%;height:100px;} header img{width:300px;height:85px;padding-left:100px;padding-top:8px;} .logo{float:left;} .nav{float:right;} .nav ul{padding-right:100px;} .nav ul li{float: left;list-style: none;width:80px;height:100px;line-height:100px;color:#333;} .main{position: relative;} .top{width:100%;height:600px;} .top img{width:100%;height:100%;} .topLayer{width:100%;height:600px;position: absolute;background-color: #000;opacity: .5;top:0;left:0;} .topLayer-top{width:500px;height:300px;position: absolute;top:280px;margin-top:-150px;z-index:2;left:50%;margin-left:-250px;} .word{padding-top:100px;color:#fff;font-size: 45px;font-weight: bold; text-align: center;} .topLayer-top button{width:200px;height:60px;margin-top:50px;color:#fff;background-color: #f5704f;font-weight: bold;text-align: center;font-size: 14px;border-radius:8px;margin-left:150px;border: 1px solid #fff;cursor: pointer;} .topLayer-top button:hover{background-color: #fff;color:#f5704f;border: 1px solid #f5704f;} .middle{width:1000px;margin:0 auto;} .common{float: left;width:33.3%;padding-top:50px;text-align: center;} .common img{width:100px;height:100px;} .com{font-size:20px;color:#7d7c7f;/*font-weight:bold;*/padding-top:20px;} .m-middle{font-size:22px;color:#e19796;font-weight:bold;padding-top:50px;font-style: italic;text-align: center;padding-bottom:50px;} .clear{clear:both;} .m-bottom{margin-bottom:20px;} .m-com{float: left;padding:10px;text-align: center;} .m-com img{width:310px;height:260px;} .des1{font-size:20px;color:#7d7d7f;padding-top:20px;} .des2{font-size:20px;color:#bdbdbc;padding-top:20px;} .bottom{background-color: #f9f9f9;padding-bottom:30px;} .bottom .content{width:1000px;margin:0 auto;} .content .title{text-align: center;font-size: 20px;color:#7d7c7f;padding:50px 0 30px 0;font-weight:bold;} .pic-content dl{width:470px;float: left;margin:10px 12px;} .pic-content dl img{width:470px;height:460px;} .pic-content dd{padding-top:15px;font-size: 16px;color:#7d7c7f;} footer{width:100%;height:100px;background-color: #292c35;color:#fff;font-size: 15px;text-align: center;line-height:100px;}
</style>
</head>
<body>
<header>
<div class="logo"><img src="img/logo.png" alt="logo"></div>
<div class="nav">
<ul>
<li>首页</li>
<li>图片</li>
<li>视频</li>
<li>手记</li>
</ul>
</div>
</header>
<div class="main">
<div class="top">
<img src="img/1.jpeg" alt="1">
</div>
<div class="topLayer"></div>
<div class="topLayer-top">
<div class="word">MY BEAUTIFUL LIFE</div>
<button>LOOK MORE ></button>
</div>
<div class="middle">
<div class="m-top">
<div class="common weixin">
<img src="img/weixin.png" alt="weixin">
<div class="com">WECHAT</div>
</div>
<div class="common weibo">
<img src="img/weibo.png" alt="weibo">
<div class="com">MICROBLOG</div>
</div>
<div class="common qq">
<img src="img/qq.png" alt="qq">
<div class="com">QQ</div>
</div>
<div class="clear"></div>
</div>
<div class="m-middle"> "I want to give good things to record down,<br>after the recall will be very beautiful." </div>
<div class="m-bottom">
<div class="m-com">
<img src="img/03-01.jpg" alt="">
<div class="des1">Cool Image</div>
<div Class="des2">Record The Picture</div>
</div>
<div class="m-com">
<img src="img/03-02.jpg" alt="">
<div class="des1">Great Picture</div>
<div class="des2">Record The Picture</div>
</div>
<div class="m-com">
<img src="img/03-03.jpg" alt="">
<div class="des1">Cool Image</div>
<div class="des2">Record The Picture</div>
</div>
<div class="clear"></div>
</div>
</div>
<div class="bottom">
<div class="content">
<div class="title">FROM THE PHOTO ALBUM</div>
<div class="pic-content">
<dl>
<dt><img src="img/04-01.jpg"></dt>
<dd>Life is like a book, just read more and more refined, more write more carefully. When read, mind open, all things have been indifferent to heart. Life is the precipitation.</dd>
</dl>
<dl>
<dt><img src="img/04-02.jpg"></dt>
<dd>Life is like a cup of tea, let people lead a person to endless aftertastes. You again good taste, it will always have a different taste, different people will have different taste more.</dd>
</dl>
<div class="clear"></div>
</div>
</div>
</div>
</div>
<footer>
© 2019 test.com 备案号xxxxxxxx号 </footer>
</body>
</html>
