How does jquery determine whether an element has a specified class name?-Front-end Q&A-php.cn

How does jquery determine whether an element has a specified class name?

青灯夜游

Release： 2022-04-20 19:25:30

Original

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Judgment method: 1. Use hasClass() to check whether the element contains the specified class name, the syntax is "element object.hasClass("class name")"; 2. Use attr() to get the value of the class attribute, and judge Whether the attribute value is equal to the specified class name, the syntax is "element object.attr("class")=="class name"".

How does jquery determine whether an element has a specified class name?

The operating environment of this tutorial: windows7 system, jquery1.10.2 version, Dell G3 computer.

There are two ways for jquery to determine whether an element contains the specified class name:

Use hasClass()
Use attr( )

Method 1: Use the hasClass()

hasClass() method to check whether the selected element contains the specified class name. This method returns "true" if the selected element contains the specified class.

<!DOCTYPE html>
<html>
	<head>
		<meta charset="UTF-8">
		<script src="js/jquery-1.10.2.min.js"></script>
		<script>
			$(document).ready(function(){
				$("button").click(function(){
					if($("p").hasClass("intro")){
						console.log("有指定类名");
					}else{
						console.log("没有指定类名");
					}
					
				});
			});
			</script>
		<style type="text/css">
			.intro {
				font-size: 120%;
				color: red;
			}
		</style>
	</head>
	<body>

		<h1>这是一个段落标题</h1>
		<p class="intro">这是一个段落</p>
		<p> 这是另外一个段落</p>
		<button>p 元素中是否有 "intro" 类</button>

	</body>
</html>

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How does jquery determine whether an element has a specified class name?

Method 2: Use attr()

attr() to get the value of the class attribute, which is the class Name

only needs to determine whether the attribute value is equal to the specified class name.

<!DOCTYPE html>
<html>
	<head>
		<meta charset="UTF-8">
		<script src="js/jquery-1.10.2.min.js"></script>
		<script>
			$(document).ready(function(){
				$("button").click(function(){
					if($("p").attr("class")=="intro"){
						console.log("有指定类名");
					}else{
						console.log("没有指定类名");
					}
					
				});
			});
			</script>
		<style type="text/css">
			.intro {
				font-size: 120%;
				color: red;
			}
		</style>
	</head>
	<body>

		<h1>这是一个段落标题</h1>
		<p class="intro">这是一个段落</p>
		<p> 这是另外一个段落</p>
		<button>p 元素中是否有 "intro" 类</button>

	</body>
</html>

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How does jquery determine whether an element has a specified class name?

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