<!DOCTYPE html>
<html lang="en">
	<head>
		<meta charset="UTF-8">
		<title>Title</title>
		<script src="js/jquery-3.5.1.min.js"></script>
		<style>
			div {
				width: 200px;
				height: 150px;
				background-color: pink;
			}
		</style>
	</head>
	<body>
		<!--$ 就是jQuery-->
		<script>
			// 等dom主要元素加载完毕执行 DomContentLoaded

			 $(document).ready(function () {
                 $('div').hide();
             })

			$(function () {
				$('div').hide();
            })
		</script>
		<div></div>
		<script>
			 $('div').hide();
		</script>
	</body>
</html>