console 命令行工具 X clear

console

function getElementsByClassName(node, className) {
	let result = [];
	let children = node.childNodes;
	for (let i = 0; i < children.length; i++) {
		if (children[i].className === className) {
			result.push(children[i]);
		}
	}
	return result;
}

let element = document.querySelector('div');
let content = getElementsByClassName(element, 'child');
console.log(content);

<!DOCTYPE html>
<html lang="en">
<head>
	<meta charset="UTF-8">
	<title>getElementByClassName</title>
</head>
<body>
	<div>
		<p class = "child">haizei</p>
		<p class = "child">haizei</p>
		<a href="#" id = "link">链接</a>
		<p class = "child">haizei</p>
	</div>
	<script type="text/javascript" src="getElementByClassName.js"></script>
</body>
</html>