<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>标题</title>
</head>
<body>
<!-- datalist 规定了input元素的选项列表 -->
<!-- 使用input的list属性来绑定datalist -->
<input list="data_list">
<datalist id="data_list">
<option value="planA">
<option value="planB">
<option value="planC">
<option value="planD">
</datalist>
</body>
</html>
展开效果: