<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8" />
<meta name="viewport" content="width=device-width, initial-scale=1">
<title></title>
<script src="jquery-3.5.1.min.js" type="text/javascript" charset="utf-8"></script>
<style type="text/css">
#box {
background-color: red;
height: 100px;
width: 100px;
border: 10px solid yellow;
margin: 10px;
}
</style>
<script type="text/javascript">
$(document).ready(function() {
$("button").eq(0).click(function() {
$("#box").height(200);
});
$("button").eq(1).click(function() {
alert($("#box").height())
});
$("button").eq(2).click(function() {
$("#box").width(300);
});
$("button").eq(3).click(function() {
alert($("#box").width())
});
});
</script>
</head>
<body>
<button type="button">设置宽度</button>
<button type="button">获取宽度</button>
<button type="button">设置高度</button>
<button type="button">获取高度</button>
<div id="box">
</div>
</body>
</html>
