代码示例:(标识:eg_js_jquery_getelementbyid)
<!DOCTYPE html>
<html>
<head>
<script src="/jquery/jquery.min.js"></script>
</head>
<body>

<h1>通过 id 查找 HTML 元素</h1>

<p id="id01">Hello World!</p>
<p id="id02">Hello China!</p>
<p id="id03">Hello Shanghai!</p>

<p id="demo"></p>

<script>
$(document).ready(function() {
  var myElements = $("#id03");
  $("#demo").text("段落 id03 的文本是:" + myElements[0].innerHTML);
});
</script>

</body>
</html>
运行结果: