【HTML+CSS】固定在页面顶端的导航条
HTML
<!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>固定在页面顶端的导航条</title>
<link rel="stylesheet" href="style.css">
<script type="text/javascript">
// s部分 : 利用了检测用户垂直滑动100像素后将其设置背景颜色，还有阴影.如果没有滑动超过100像素，背景颜色为透明，阴影设置为无.
window.onload = function () {
var nav = document.getElementsByClassName(nav)[0];
window.onscroll = function () {
if (window.pageYOffset > 100) {
nav.style.background = "#3498db";
nav.style.boxShadow = "0px 4px 2px #2980b9";
} else {
nav.style.background = "transparent";
nav.style.boxShadow = "none";
}
}
}
</script>
</head>
<body>
<div class="header">
<div class="nav">
<ul>
<li><a href="#">Home</a></li>
<li><a href="#">Blog</a></li>
<li><a href="#">Info</a></li>
<li><a href="#">Contact</a></li>
<li><a href="#">About</a></li>
</ul>
</div>
</div>
<div class="box"></div>
</body>
</html>
CSS
* {
padding: 0;
margin: 0;
box-sizing: border-box;
}
.header {
width: 100%;
height: 800px;
background-image: url(bg.png);
background-size: cover;
}
.nav {
width: 100%;
padding: 20px;
position: fixed;
top: 0;
text-align: center;
transition: .5s;
}
.nav ul li {
list-style-type: none;
display: inline-block;
padding: 10px 50px;
font-size: 24px;
font-family: sans-serif;
cursor: pointer;
border-radius: 10px;
transition: .5s;
}
.nav ul li a{
color: #fff;
text-decoration:none;
}
.nav ul li:hover {
background: #f39c12;
}
.box {
width: 80%;
height: 2000px;
margin: 20px auto;
}
