在输入表单上，我检查输入的成本值。但是运行脚本找不到表单input01。
这就是它的工作原理：

<form name="form01" th:method="POST" th:action="@{/add-car/new}" th:object="${carEntity}">
        <input type="text" name="input01">
        ...
        <button type="submit" class="btn btn-primary" onclick="check()">Save</button>
    </form>
    <script>
        function check() {
            let inputVal = document.forms["form01"]["input01"].value;
            OK!!!
            ....
        }
    </script>

但不是这样的：

<form name="form01" th:method="POST" th:action="@{/add-car/new}" th:object="${carEntity}">
        <input type="text" name="input01" th:field="*{cost}">
        ...
        <button type="submit" class="btn btn-primary" onclick="check()">Save</button>
    </form>
    <script>
        function check() {
            let inputVal = document.forms["form01"]["input01"].value;
            Where Error:
            "Uncaught TypeError: document.forms.form01.input01 is undefined"

            ....
        }
    </script>

我做错什么了？