无法获得表/列表中的最后一个值

Question

我无法获取上一项的值并相应地更新下一项，不确定我该怎么做。我也尝试过:last-child，但似乎没有返回所需的值。

if ($("tbody").children().length == 0) {

            var item = `<tr>
                            <th scope="row">1</th>
                            <td>
                                <p>This is a paragraph</p>
                            </td>
                            <td>
                                <button type="button" class="btn btn-success" style="margin-right:1rem;">Complete</button>
                                <button type="button" class="btn btn-light">Edit</button>
                            </td>
                        </tr>`

            $("tbody").append(item);
        } else {
            var lastValue = parseInt($("tbody th:last-of-type").html());
            item = `<tr><th scope="row">` + (lastValue + 1) + `</th>
                                                                <td>
                                                                    <p>This is a para</p>
                                                                </td>
                                                                <td>
                                                                    <button type="button" class="btn btn-success" style="margin-right:1rem;">Complete</button>
                                                                    <button type="button" class="btn btn-light">Edit</button>
                                                                </td></tr>`

            $("tbody").append(item);
        }

Answer 1

我使用:last-of-type代替了:last，它似乎返回了正确的值，并且我能够相应地更新行数。

if ($("tbody").children().length == 0) {

                var item = `<tr>
                                <th scope="row">1</th>
                                <td>
                                    <p>This is a paragraph</p>
                                </td>
                                <td>
                                    <button type="button" class="btn btn-success" style="margin-right:1rem;">Complete</button>
                                    <button type="button" class="btn btn-light">Edit</button>
                                </td>
                            </tr>`

                $("tbody").append(item);
            } else {
                var lastValue = parseInt($("tbody th:last").html());
                item = `<tr><th scope="row">` + (lastValue + 1) + `</th>
                                                                    <td>
                                                                        <p>This is a para</p>
                                                                    </td>
                                                                    <td>
                                                                        <button type="button" class="btn btn-success" style="margin-right:1rem;">Complete</button>
                                                                        <button type="button" class="btn btn-light">Edit</button>
                                                                    </td></tr>`

                $("tbody").append(item);
            }