js选项卡效果的“ active”前面有个空格_js类名active前面加不加空格的区别-优快云博客

本文链接：https://blog.youkuaiyun.com/caa112/article/details/102502916

本文介绍了一个使用HTML、CSS和JavaScript实现的选项卡组件，详细展示了如何通过简单的代码创建交互式的选项卡界面，包括样式定制和功能实现。

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代码：

	<!DOCTYPE html>
<html lang="zh">
	<head>
		<meta charset="UTF-8">
		<meta name="viewport" content="width=device-width, initial-scale=1.0">
		<meta http-equiv="X-UA-Compatible" content="ie=edge">
		<title>选项卡</title>
		<style type="text/css">
			body {
				font-family: "Lato", sans-serif;
			}

			/* Style the tab */
			div.tab {
				overflow: hidden;
				border: 1px solid #ccc;
				background-color: #f1f1f1;
			}

			/* Style the buttons inside the tab */
			div.tab button {
				background-color: inherit;
				float: left;
				border: none;
				outline: none;
				cursor: pointer;
				padding: 14px 16px;
				transition: 0.3s;
				font-size: 17px;
			}

			/* Change background color of buttons on hover */
			div.tab button:hover {
				background-color: #ddd;
			}

			/* Create an active/current tablink class */
			div.tab button.active {
				background-color: red;
			}

			/* Style the tab content */
			.tabcontent {
				display: none;
				padding: 6px 12px;
				border: 1px solid #ccc;
				border-top: none;
			}
		</style>
	</head>
	<body>
		<div class="tab">
			<button class="tablinks" οnclick="openCity(event, 'London')">London</button>
			<button class="tablinks" οnclick="openCity(event, 'Paris')">Paris</button>
			<button class="tablinks" οnclick="openCity(event, 'Tokyo')">Tokyo</button>
		</div>

		<div id="London" class="tabcontent">
			<h3>London</h3>
			<p>London is the capital city of England.</p>
		</div>

		<div id="Paris" class="tabcontent">
			<h3>Paris</h3>
			<p>Paris is the capital of France.</p>
		</div>

		<div id="Tokyo" class="tabcontent">
			<h3>Tokyo</h3>
			<p>Tokyo is the capital of Japan.</p>
		</div>
		<script type="text/javascript">
			function openCity(evt, cityName) {
				var i, tabcontent, tablinks;
				tabcontent = document.getElementsByClassName("tabcontent");
				tablinks = document.getElementsByClassName("tablinks");

				//所有tabcontent隐藏
				for (i = 0; i < tabcontent.length; i++) {
					tabcontent[i].style.display = "none";
				}
				//所有tablinks的active属性设置为空
				for (i = 0; i < tablinks.length; i++) {
					tablinks[i].className = tablinks[i].className.replace("active", "");
				}

				document.getElementById(cityName).style.display = "block";
				evt.currentTarget.className+=" active"; //currentTarget返回当前绑定事件节点,//active前没有空格,会失效背景颜色,因为这个是在原有class（tabcontent）再添加一个class,两个class直接要有空格隔开,否则class没效果.
			}
		</script>
	</body>
</html>