固定定位 position:fixed
固定定位是相对与浏览器窗口来定位, 就算页面滚动, 固定定位元素的位置不会变
固定定位元素脱离了标准文档流, 会雅盖主标准文档流里的元素
固定定位元素不再占用空间
<pre spellcheck="false" class="md-fences md-end-block md-fences-with-lineno ty-contain-cm modeLoaded" lang="css" contenteditable="true" cid="n5" mdtype="fences" style="box-sizing: border-box; overflow: visible; font-family: var(--monospace); font-size: 0.9em; display: block; break-inside: avoid; text-align: left; white-space: normal; background-image: inherit; background-position: inherit; background-size: inherit; background-repeat: inherit; background-attachment: inherit; background-origin: inherit; background-clip: inherit; background-color: rgb(248, 248, 248); position: relative !important; border: 1px solid rgb(231, 234, 237); border-radius: 3px; padding: 8px 4px 6px 0px; margin-bottom: 15px; margin-top: 15px; width: inherit; color: rgb(51, 51, 51); font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-indent: 0px; text-transform: none; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;"> <html>
<head>
<style type="text/css">
p.one {
position: fixed;
left: 5px;
top: 5px;
}
p.two {
position: fixed;
top: 30px;
right: 5px;
}
</style>
</head>
<body>
<p class="one">一些文本。</p>
<p class="two">更多的文本。</p>
</body>
</html></pre>
顶部导航栏实例
<pre spellcheck="false" class="md-fences md-end-block md-fences-with-lineno ty-contain-cm modeLoaded" lang="css" contenteditable="true" cid="n8" mdtype="fences" style="box-sizing: border-box; overflow: visible; font-family: var(--monospace); font-size: 0.9em; display: block; break-inside: avoid; text-align: left; white-space: normal; background-image: inherit; background-position: inherit; background-size: inherit; background-repeat: inherit; background-attachment: inherit; background-origin: inherit; background-clip: inherit; background-color: rgb(248, 248, 248); position: relative !important; border: 1px solid rgb(231, 234, 237); border-radius: 3px; padding: 8px 4px 6px 0px; margin-bottom: 15px; margin-top: 15px; width: inherit; color: rgb(51, 51, 51); font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-indent: 0px; text-transform: none; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;"> <!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta http-equiv="X-UA-Compatible" content="ie=edge">
<title>Document</title>
<style>
{
margin:0;
padding: 0;
}
.nav{
width:100%;
height:60px;
background-color: cornflowerblue;
/固定定位*/
position:fixed;
left:0px;
top:0px;
}
.nav .inner_c{
width:1000px;
height: 60px;
margin:0px auto;
}
ul{
list-style: none;
}
ul li{
float:left;
width:100px;
height:60px;
line-height: 60px;
text-align: center;
}
ul li a{
display: block;
width:100px;
height: 60px;
text-decoration: none;
color:white;
font-weight: bold;
}
ul li a:hover{
background-color: gold;
}
</style>
</head>
<body>
<div class="nav">
<div class="inner_c">
<ul>
<li><a href="#">网站栏目</a></li>
<li><a href="#">网站栏目</a></li>
<li><a href="#">网站栏目</a></li>
<li><a href="#">网站栏目</a></li>
<li><a href="#">网站栏目</a></li>
<li><a href="#">网站栏目</a></li>
<li><a href="#">网站栏目</a></li>
<li><a href="#">网站栏目</a></li>
<li><a href="#">网站栏目</a></li>
<li><a href="#">网站栏目</a></li>
</ul>
</div>
</div>
<img src="https://ss.csdn.net/p?https://mmbiz.qpic.cn/mmbiz_png/BnSNEaficFAbAbJYFwdEziciaSOsbuD2yjicTxRthcMShOSnCcU6Dj06bbV4ibkfiaxibqC3fSAz3AcmmKLA9VPu3ErMg/640?wx_fmt=png">
<img src="https://ss.csdn.net/p?https://mmbiz.qpic.cn/mmbiz_png/BnSNEaficFAbAbJYFwdEziciaSOsbuD2yjicTxRthcMShOSnCcU6Dj06bbV4ibkfiaxibqC3fSAz3AcmmKLA9VPu3ErMg/640?wx_fmt=png">
<img src="https://ss.csdn.net/p?https://mmbiz.qpic.cn/mmbiz_png/BnSNEaficFAbAbJYFwdEziciaSOsbuD2yjicTxRthcMShOSnCcU6Dj06bbV4ibkfiaxibqC3fSAz3AcmmKLA9VPu3ErMg/640?wx_fmt=png">
<img src="https://ss.csdn.net/p?https://mmbiz.qpic.cn/mmbiz_png/BnSNEaficFAbAbJYFwdEziciaSOsbuD2yjicTxRthcMShOSnCcU6Dj06bbV4ibkfiaxibqC3fSAz3AcmmKLA9VPu3ErMg/640?wx_fmt=png">
<img src="https://ss.csdn.net/p?https://mmbiz.qpic.cn/mmbiz_png/BnSNEaficFAbAbJYFwdEziciaSOsbuD2yjicTxRthcMShOSnCcU6Dj06bbV4ibkfiaxibqC3fSAz3AcmmKLA9VPu3ErMg/640?wx_fmt=png">
</body>
</html></pre>
