<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap.min.css" integrity="sha384-BVYiiSIFeK1dGmJRAkycuHAHRg32OmUcww7on3RYdg4Va+PmSTsz/K68vbdEjh4u" crossorigin="anonymous">
</head>
<body>
<div id="carousel-example-generic" class="carousel slide" data-ride="carousel">
<!-- Indicators -->
<ol class="carousel-indicators">
<li data-target="#carousel-example-generic" data-slide-to="0" class="active"></li>
<li data-target="#carousel-example-generic" data-slide-to="1"></li>
<li data-target="#carousel-example-generic" data-slide-to="2"></li>
</ol>
<!-- Wrapper for slides -->
<div class="carousel-inner" role="listbox">
<div class="item active">
<img src="http://ichef.bbci.co.uk/news/976/cpsprodpb/87D3/production/_84817743_beckhamfashion.jpg" alt="...">
<div class="carousel-caption">
...
</div>
</div>
<div class="item">
<img src="http://ichef.bbci.co.uk/news/976/cpsprodpb/9949/production/_84814293_dummy.jpg" alt="...">
<div class="carousel-caption">
...
</div>
</div>
...
</div>
<!-- Controls -->
<a class="left carousel-control" href="#carousel-example-generic" role="button" data-slide="prev">
<span class="glyphicon glyphicon-chevron-left" aria-hidden="true"></span>
<span class="sr-only">Previous</span>
</a>
<a class="right carousel-control" href="#carousel-example-generic" role="button" data-slide="next">
<span class="glyphicon glyphicon-chevron-right" aria-hidden="true"></span>
<span class="sr-only">Next</span>
</a>
</div>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.12.4/jquery.min.js"></script>
<script src="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/js/bootstrap.min.js" integrity="sha384-Tc5IQib027qvyjSMfHjOMaLkfuWVxZxUPnCJA7l2mCWNIpG9mGCD8wGNIcPD7Txa" crossorigin="anonymous"></script>
</body>
</html>例如，我正在使用 bootstap carousel；
<div id="carousel-example-generic" class="carousel slide" data-ride="carousel">
<div class="carousel-inner" role="listbox">
<div class="item active">
<img src="..." alt="...">
<div class="carousel-caption">
</div>
</div>
<div class="item">
<img src="..." alt="...">
<div class="carousel-caption">
...
</div>
</div>
</div>
<!-- Controls -->
<a class="left carousel-control" href="#carousel-example-generic" role="button" data-slide="prev">
<span class="glyphicon glyphicon-chevron-left" aria-hidden="true"></span>
<span class="sr-only">Previous</span>
</a>
<a class="right carousel-control" href="#carousel-example-generic" role="button" data-slide="next">
<span class="glyphicon glyphicon-chevron-right" aria-hidden="true"></span>
<span class="sr-only">Next</span>
</a>
</div>
正如您所看到的，我的第一个 .item 类具有 .active 类，但我想在删除 .active 类时自动添加它来自 .item 类，然后 javascript 给了我这个错误: TypeError: Cannot read property 'offsetWidth' of undefined/works/anitur/js/bootstrap.min.js:6 和我尝试使用此代码添加
$(".carousel > .item:first").addClass("active");
但是什么都没有改变我怎么能实现我想要的呢？顺便问一下，有没有办法用js而不是html添加轮播控件？
最佳答案
最好的做法是在 HTML 模板本身中添加轮播类。为什么是因为轮播插件会在文档准备好后重建 HTML。不过您可以尝试下面的代码。
$(".carousel .item").first().addClass("active");
关于javascript - 为第一项元素添加事件类，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/41713070/