极客教程如何在Bootstrap中设置ScrollSpy的偏移属性
Offset是Bootstrap Scrollspy的一个属性，用户可以在计算滚动位置时指定从顶部偏移的像素。当用户觉得导航条或列表提前改变状态或在冲浪时不需要时，它就变得很有用。它总是一个数字，默认值是10。该值可以通过JavaScript或在body标签中加入data-offset值来改变。
语法:
- Normal Declaration
(body data-offset="")
- JavaScript Declaration
$(document).ready(function(){
$('body').scrollspy({target: " ", offset: });
});
例子1：这个例子描述了bootstrap导航条，其中使用了四个部分，使用JavaScript将偏移量属性设置为60。
<!DOCTYPE html>
<html>
<head>
<title>Bootstrap offset property</title>
<meta charset="utf-8">
<meta name="viewport" content=
"width=device-width, initial-scale=1">
<link rel="stylesheet" href=
"https://maxcdn.bootstrapcdn.com/bootstrap/3.4.1/css/bootstrap.min.css">
<script src=
"https://ajax.googleapis.com/ajax/libs/jquery/3.5.1/jquery.min.js">
</script>
<script src=
"https://maxcdn.bootstrapcdn.com/bootstrap/3.4.1/js/bootstrap.min.js">
</script>
<style>
body {
position: relative;
}
#section1 {
padding-top: 50px;
height: 600px;
background-color: #32CD32;
}
#section2 {
padding-top: 50px;
height: 600px;
background-color: #FFFF00;
}
#section3 {
padding-top: 50px;
height: 600px;
background-color: #00FF00;
}
#section4 {
padding-top: 50px;
height: 600px;
background-color: #FF0000;
}
</style>
</head>
<body>
<nav class="navbar navbar-dark bg-success
navbar-fixed-top">
<div class="container-fluid">
<div class="navbar-header">
<button type="button" class="navbar-toggle"
data-toggle="collapse"
data-target="#myNavbar">
<span class="icon-bar"></span>
<span class="icon-bar"></span>
<span class="icon-bar"></span>
</button>
<a class="navbar-brand" href="#">
GeeksforGeeks
</a>
</div>
<div>
<div class="collapse navbar-collapse"
id="myNavbar">
<ul class="nav navbar-nav">
<li><a href="#section1">Section 1</a></li>
<li><a href="#section2">Section 2</a></li>
<li><a href="#section3">Section 3</a></li>
<li><a href="#section4">Section 4</a></li>
</ul>
</div>
</div>
</div>
</nav>
<div id="section1" class="container-fluid">
<h1>Section 1</h1>
<hr>
<p>
GeeksforGeeks is a computer science
portal. It was created with a goal
in mind to provide well written, well
thought and well explained solutions
for selected questions. The core team
of five super geeks constituting of
technology lovers and computer science
enthusiasts have been constantly working
in this direction.
GeeksforGeeks is a computer science
portal. It was created with a goal
in mind to provide well written, well
thought and well explained solutions
for selected questions. The core team
of five super geeks constituting of
technology lovers and computer science
enthusiasts have been constantly working
in this direction.
</p>
</div>
<div id="section2" class="container-fluid">
<h1>Section 2</h1>
<hr>
<p>
GeeksforGeeks is a computer science
portal. It was created with a goal
in mind to provide well written, well
thought and well explained solutions
for selected questions. The core team
of five super geeks constituting of
technology lovers and computer science
enthusiasts have been constantly working
in this direction.
GeeksforGeeks is a computer science
portal. It was created with a goal
in mind to provide well written, well
thought and well explained solutions
for selected questions. The core team
of five super geeks constituting of
technology lovers and computer science
enthusiasts have been constantly working
in this direction.
</p>
</div>
<div id="section3" class="container-fluid">
<h1>Section 3</h1>
<hr>
<p>
GeeksforGeeks is a computer science
portal. It was created with a goal
in mind to provide well written, well
thought and well explained solutions
for selected questions. The core team
of five super geeks constituting of
technology lovers and computer science
enthusiasts have been constantly working
in this direction.
GeeksforGeeks is a computer science
portal. It was created with a goal
in mind to provide well written, well
thought and well explained solutions
for selected questions. The core team
of five super geeks constituting of
technology lovers and computer science
enthusiasts have been constantly working
in this direction.
</p>
</div>
<div id="section4" class="container-fluid">
<h1>Section 4</h1>
<hr>
<p>
GeeksforGeeks is a computer science
portal. It was created with a goal
in mind to provide well written, well
thought and well explained solutions
for selected questions. The core team
of five super geeks constituting of
technology lovers and computer science
enthusiasts have been constantly working
in this direction.
GeeksforGeeks is a computer science
portal. It was created with a goal
in mind to provide well written, well
thought and well explained solutions
for selected questions. The core team
of five super geeks constituting of
technology lovers and computer science
enthusiasts have been constantly working
in this direction.
</p>
</div>
<script>
(document).ready(function () {
('body').scrollspy({
target: ".navbar", offset: 50
});
});
</script>
</body>
</html>
输出:
示例2：该示例描述了bootstrap list-group，其中使用了三个部分，并且在body标签中设置了15的offset属性。
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="utf-8">
<meta name="viewport" content=
"width=device-width, initial-scale=1,
shrink-to-fit=no">
<title>Bootstrap 4 ScrollSpy</title>
<link rel="stylesheet" href=
"https://stackpath.bootstrapcdn.com/bootstrap/4.3.1/css/bootstrap.min.css">
<link rel="stylesheet" href=
"https://maxcdn.bootstrapcdn.com/font-awesome/4.7.0/css/font-awesome.min.css">
<script src=
"https://ajax.googleapis.com/ajax/libs/jquery/3.3.1/jquery.min.js">
</script>
<script src=
"https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.14.7/umd/popper.min.js">
</script>
<script src=
"https://stackpath.bootstrapcdn.com/bootstrap/4.3.1/js/bootstrap.min.js">
</script>
<style>
body {
position: relative;
/* required */
}
.list-group {
position: sticky;
top: 20px;
}
</style>
</head>
<body data-spy="scroll" data-offset="20"
data-target="#myScrollspy">
<div class="container">
<h1>Bootstrap Scrollspy</h1>
<br>
<div class="row">
<div class="col-sm-3" id="myScrollspy">
<div class="list-group">
<a class="list-group-item
list-group-item-action active"
href="#section1">Section One
</a>
<a class="list-group-item
list-group-item-action"
href="#section2">Section Two
</a>
<a class="list-group-item
list-group-item-action"
href="#section3">Section Three
</a>
</div>
</div>
<div class="col-sm-9">
<div id="section1">
<h2>Section One</h2>
<p>
GeeksforGeeks is a computer science portal. It was created with a goal
in mind to provide well written, well thought and well explained solutions
for selected questions. The core team of five super geeks constituting of
technology lovers and computer science enthusiasts have been constantly
working in this direction. GeeksforGeeks is a computer science portal.
It was created with a goal in mind to provide well written, well thought
and well explained solutions for selected questions. The core team of five
super geeks constituting of technology lovers and computer science
enthusiasts have been constantly working in this direction.
GeeksforGeeks is a computer science portal. It was created with a goal
in mind to provide well written, well thought and well explained solutions
for selected questions. The core team of five super geeks constituting of
technology lovers and computer science enthusiasts have been constantly
working in this direction. GeeksforGeeks is a computer science portal.
It was created with a goal in mind to provide well written, well thought
and well explained solutions for selected questions. The core team of five
super geeks constituting of technology lovers and computer science
enthusiasts have been constantly working in this direction.
</p>
</div>
<hr>
<div id="section2">
<h2>Section Two</h2>
<p>
GeeksforGeeks is a computer science portal. It was created with a goal
in mind to provide well written, well thought and well explained solutions
for selected questions. The core team of five super geeks constituting of
technology lovers and computer science enthusiasts have been constantly
working in this direction. GeeksforGeeks is a computer science portal.
It was created with a goal in mind to provide well written, well thought
and well explained solutions for selected questions. The core team of five
super geeks constituting of technology lovers and computer science
enthusiasts have been constantly working in this direction.
GeeksforGeeks is a computer science portal. It was created with a goal
in mind to provide well written, well thought and well explained solutions
for selected questions. The core team of five super geeks constituting of
technology lovers and computer science enthusiasts have been constantly
working in this direction. GeeksforGeeks is a computer science portal.
It was created with a goal in mind to provide well written, well thought
and well explained solutions for selected questions. The core team of five
super geeks constituting of technology lovers and computer science
enthusiasts have been constantly working in this direction.
</p>
</div>
<hr>
<div id="section3">
<h2>Section Three</h2>
<p>
GeeksforGeeks is a computer science portal. It was created with a goal
in mind to provide well written, well thought and well explained solutions
for selected questions. The core team of five super geeks constituting of
technology lovers and computer science enthusiasts have been constantly
working in this direction. GeeksforGeeks is a computer science portal.
It was created with a goal in mind to provide well written, well thought
and well explained solutions for selected questions. The core team of five
super geeks constituting of technology lovers and computer science
enthusiasts have been constantly working in this direction.
GeeksforGeeks is a computer science portal. It was created with a goal
in mind to provide well written, well thought and well explained solutions
for selected questions. The core team of five super geeks constituting of
technology lovers and computer science enthusiasts have been constantly
working in this direction. GeeksforGeeks is a computer science portal.
It was created with a goal in mind to provide well written, well thought
and well explained solutions for selected questions. The core team of five
super geeks constituting of technology lovers and computer science
enthusiasts have been constantly working in this direction.
</p>
</div>
<hr>
</div>
</div>
</div>
</body>
</html>
输出:
