方法1：使用hasClass()方法:hasClass()是jQuery中的内置方法, 用于检查具有指定类名的元素是否存在。它返回一个布尔值, 指定该类是否存在于元素中。这可用于检查多个类。
语法如下：
$('element').hasClass('className')例子：
<!DOCTYPE html>
<html>
<head>
<title>
How to check an element contains
a class using jQuery?
</title>
<script src =
"https://code.jquery.com/jquery-3.3.1.min.js">
</script>
</head>
<body>
<h1 style = "color: green">
lsbin
</h1>
<b>
How to check an element contains
a class using jQuery?
</b>
<p class = "example-class">
This element has "example-class".
</p>
<p>Does the element have class?
<span class = "output"></span>
</p>
<button onclick = "checkForClass()">
Click to check
</button>
<!-- Script to use hasClass() method to
check the existence of class name -->
<script type = "text/javascript">
function checkForClass() {
classCheck = $('p').is('.example-class');
document.querySelector('.output').textContent
= classCheck;
}
</script>
</body>
</html>输出如下：
方法2：使用is()方法:这类似于以上方法, 并且可以根据需要用于检查更多属性。选择必需元素, 然后像CSS类选择器一样传递类名。它返回一个布尔值, 指定该类是否存在于元素中。这可用于检查多个类。
语法如下：
$('element').is('.className')例子：
<!DOCTYPE html>
<html>
<head>
<title>
How to check an element contains
a class using jQuery?
</title>
<script src =
"https://code.jquery.com/jquery-3.3.1.min.js">
</script>
</head>
<body>
<h1 style = "color: green">
lsbin
</h1>
<b>
How to check an element contains
a class using jQuery?
</b>
<p class = "example-class">
This element has "example-class".
</p>
<p>Does the element have class?
<span class = "output"></span>
</p>
<button onclick = "checkForClass()">
Click to check
</button>
<!-- Script to use is() method to
check the existence of class name -->
<script type = "text/javascript">
function checkForClass() {
classCheck = $('p').is('.example-class');
document.querySelector('.output').textContent
= classCheck;
}
</script>
</body>
</html>输出如下：
