<html><head><script src="https://ajax.aspnetcdn.com/ajax/jQuery/jquery-3.5.1.min.js"></script><script>$(document).ready(function(){ $(document).ajaxError(function(){ alert("An error occured!"); }); $("button").click(function(){ $("div").load("wrongfile.txt"); });});</script></head><body><div><h2>让 AJAX 更改此文本</h2></div><button>更改内容</button></body></html>