<html>
<body>
<form action="form-action.phpp">
日期: <input type="datetime" id="myDatetime" name="date" required>
<input type="submit">
</form>
<p>点击 "点我" 按钮查看 datetime 字段是否为变得的必填部分。</p>
<button onclick="myFunction()">点我</button>
<p id="demo"></p>
<script>
function myFunction() {
var x = document.getElementById("myDatetime").required;
document.getElementById("demo").innerHTML = x;
}
</script>
</body>
</html>