<html><head><script src="https://ajax.aspnetcdn.com/ajax/jQuery/jquery-3.4.1.min.js"></script></head><body><h2>通过查询选择器查找 HTML 元素</h2><p class="intro">Hello World!</p><p class="intro">Hello Sweden!</p><p class="intro">Hello Japan!</p><p id="demo"></p><script>$(document).ready(function() { var myElements = $("p.intro"); $("#demo").text("第一段 class='intro' 是：" + myElements[0].innerHTML);});</script></body></html>