<!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>