出现以下错误是什么意思？
enter code here
代码：
enter code here
<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
pageEncoding="ISO-8859-1"%>
<%@taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<%@taglib prefix="spring" uri="http://www.springframework.org/tags" %>
<spring:url var="css" value="/resources/css"/>
<spring:url var="js" value="/resources/js"/>
<spring:url var="images" value="/resources/images"/>
<c:set var="contextRoot" value="${pageContext.request.contextPath } "/>
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no">
<meta name="description" content="">
<meta name="author" content="">
<title>Shop Homepage - Start Bootstrap Template</title>
<!-- Bootstrap core CSS -->
<link href="${css}/bootstrap.min.css" rel="stylesheet">
<!-- Custom styles for this template -->
<link href="${css}/myapp.css" rel="stylesheet">
</head>
<body>
<!-- Navigation -->
<nav class="navbar navbar-expand-lg navbar-dark bg-dark fixed-top">
<div class="container">
<a class="navbar-brand" href="#">Start Bootstrap</a>
<button class="navbar-toggler" type="button" data-toggle="collapse" data-target="#navbarResponsive" aria-controls="navbarResponsive" aria-expanded="false" aria-label="Toggle navigation">
<span class="navbar-toggler-icon"></span>
</button>
<div class="collapse navbar-collapse" id="navbarResponsive">
<ul class="navbar-nav ml-auto">
<li class="nav-item active">
<a class="nav-link" href="#">Home
<span class="sr-only">(current)</span>
</a>
</li>
<li class="nav-item">
<a class="nav-link" href="#">About</a>
</li>
<li class="nav-item">
<a class="nav-link" href="#">Services</a>
</li>
<li class="nav-item">
<a class="nav-link" href="#">Contact</a>
</li>
</ul>
</div>
</div>
</nav>
<!-- Page Content -->
<div class="container">
<div class="row">
<div class="col-lg-3">
<h1 class="my-4">Shop Name</h1>
<div class="list-group">
<a href="#" class="list-group-item">Category 1</a>
<a href="#" class="list-group-item">Category 2</a>
<a href="#" class="list-group-item">Category 3</a>
</div>
</div>
<!-- /.col-lg-3 -->
<div class="col-lg-9">
<div id="carouselExampleIndicators" class="carousel slide my-4" data-ride="carousel">
<ol class="carousel-indicators">
<li data-target="#carouselExampleIndicators" data-slide-to="0" class="active"></li>
<li data-target="#carouselExampleIndicators" data-slide-to="1"></li>
<li data-target="#carouselExampleIndicators" data-slide-to="2"></li>
</ol>
<div class="carousel-inner" role="listbox">
<div class="carousel-item active">
<img class="d-block img-fluid" src="http://placehold.it/900x350" alt="First slide">
</div>
<div class="carousel-item">
<img class="d-block img-fluid" src="http://placehold.it/900x350" alt="Second slide">
</div>
<div class="carousel-item">
<img class="d-block img-fluid" src="http://placehold.it/900x350" alt="Third slide">
</div>
</div>
<a class="carousel-control-prev" href="#carouselExampleIndicators" role="button" data-slide="prev">
<span class="carousel-control-prev-icon" aria-hidden="true"></span>
<span class="sr-only">Previous</span>
</a>
<a class="carousel-control-next" href="#carouselExampleIndicators" role="button" data-slide="next">
<span class="carousel-control-next-icon" aria-hidden="true"></span>
<span class="sr-only">Next</span>
</a>
</div>
<div class="row">
<div class="col-lg-4 col-md-6 mb-4">
<div class="card h-100">
<a href="#"><img class="card-img-top" src="http://placehold.it/700x400" alt=""></a>
<div class="card-body">
<h4 class="card-title">
<a href="#">Item One</a>
</h4>
<h5>$24.99</h5>
<p class="card-text">Lorem ipsum dolor sit amet, consectetur adipisicing elit. Amet numquam aspernatur!</p>
</div>
<div class="card-footer">
<small class="text-muted">★ ★ ★ ★ ☆</small>
</div>
</div>
</div>
<div class="col-lg-4 col-md-6 mb-4">
<div class="card h-100">
<a href="#"><img class="card-img-top" src="http://placehold.it/700x400" alt=""></a>
<div class="card-body">
<h4 class="card-title">
<a href="#">Item Two</a>
</h4>
<h5>$24.99</h5>
<p class="card-text">Lorem ipsum dolor sit amet, consectetur adipisicing elit. Amet numquam aspernatur! Lorem ipsum dolor sit amet.</p>
</div>
<div class="card-footer">
<small class="text-muted">★ ★ ★ ★ ☆</small>
</div>
</div>
</div>
<div class="col-lg-4 col-md-6 mb-4">
<div class="card h-100">
<a href="#"><img class="card-img-top" src="http://placehold.it/700x400" alt=""></a>
<div class="card-body">
<h4 class="card-title">
<a href="#">Item Three</a>
</h4>
<h5>$24.99</h5>
<p class="card-text">Lorem ipsum dolor sit amet, consectetur adipisicing elit. Amet numquam aspernatur!</p>
</div>
<div class="card-footer">
<small class="text-muted">★ ★ ★ ★ ☆</small>
</div>
</div>
</div>
<div class="col-lg-4 col-md-6 mb-4">
<div class="card h-100">
<a href="#"><img class="card-img-top" src="http://placehold.it/700x400" alt=""></a>
<div class="card-body">
<h4 class="card-title">
<a href="#">Item Four</a>
</h4>
<h5>$24.99</h5>
<p class="card-text">Lorem ipsum dolor sit amet, consectetur adipisicing elit. Amet numquam aspernatur!</p>
</div>
<div class="card-footer">
<small class="text-muted">★ ★ ★ ★ ☆</small>
</div>
</div>
</div>
<div class="col-lg-4 col-md-6 mb-4">
<div class="card h-100">
<a href="#"><img class="card-img-top" src="http://placehold.it/700x400" alt=""></a>
<div class="card-body">
<h4 class="card-title">
<a href="#">Item Five</a>
</h4>
<h5>$24.99</h5>
<p class="card-text">Lorem ipsum dolor sit amet, consectetur adipisicing elit. Amet numquam aspernatur! Lorem ipsum dolor sit amet.</p>
</div>
<div class="card-footer">
<small class="text-muted">★ ★ ★ ★ ☆</small>
</div>
</div>
</div>
<div class="col-lg-4 col-md-6 mb-4">
<div class="card h-100">
<a href="#"><img class="card-img-top" src="http://placehold.it/700x400" alt=""></a>
<div class="card-body">
<h4 class="card-title">
<a href="#">Item Six</a>
</h4>
<h5>$24.99</h5>
<p class="card-text">Lorem ipsum dolor sit amet, consectetur adipisicing elit. Amet numquam aspernatur!</p>
</div>
<div class="card-footer">
<small class="text-muted">★ ★ ★ ★ ☆</small>
</div>
</div>
</div>
</div>
<!-- /.row -->
</div>
<!-- /.col-lg-9 -->
</div>
<!-- /.row -->
</div>
<!-- /.container -->
<!-- Footer -->
<footer class="py-5 bg-dark">
<div class="container">
<p class="m-0 text-center text-white">Copyright © Your Website 2019</p>
</div>
<!-- /.container -->
</footer>
<!-- Bootstrap core JavaScript -->
<script src="${js}/jquery.js"></script>
<script src="${js}/bootstrap.min.js"></script>
</body>
</html>
答案 0 :(得分：0)
错误很明显，您正在尝试读取没有使用选择器的元素的属性offsetWidth，或者没有这样的元素。从元素中删除offsetWidth或请确认是否存在类似的元素
另一种情况是使用引导插件，例如缺少类名的滑块或不遵循插件所具有模式的代码。在这种情况下也可能发生这种错误。
例如：没有在任何幻灯片上设置active类的引导滑块。