PHP多页面表单数据传递：使用隐藏字段实现数据流转

<form action="form2.php" method="post">
    <!-- ... 其他表单元素 ... -->

    <div class="form-row-child">
        <label for="month">Month</label>
        <select class="form-select" aria-label="Default select example" name="month" id="month">
            <option selected disabled>Select Month</option>
            <option value="January">January</option>
            <option value="February">February</option>
            <option value="March">March</option>
            <option value="April">April</option>
            <option value="May">May</option>
            <option value="June">June</option>
            <option value="July">July</option>
            <option value="August">August</option>
            <option value="September">September</option>
            <option value="October">October</option>
            <option value="November">November</option>
            <option value="December">December</option>
        </select>
    </div>
    <!-- ... 其他表单元素 ... -->
    <input type="submit" class="btn btn-danger form1-btn" value="Proceed">
</form>

<?php
// 假设 form2.php 会进行一些处理，例如：
// $vagueEmployee = new Employee(); // 示例对象
// $salaryPerHour = calculateSalaryPerHour(); // 示例函数
// $payFor13thMonth = calculate13thMonthPay(); // 示例函数

// 确保从 form1.php 接收到 'month' 值
$monthFromForm1 = isset($_POST['month']) ? htmlspecialchars($_POST['month']) : '';
?>

<form action="form3.php" method="post">
    <!-- ... form2.php 的其他表单元素 ... -->

    <!-- 新增：用于将 'month' 值传递给 form3.php 的隐藏字段 -->
    <input type="hidden" name="month" value="<?php echo $monthFromForm1; ?>">

    <!-- ... form2.php 的其他表单元素，例如： -->
    <div class="half-form-child">
        <label for="holidayReg">Regular (Per day)</label>
        <select class="form-select" aria-label="Default select example" name="holidayReg" id="holidayReg">
        <?php // foreach ($regHolidays as $value) { ?>
            <!-- <option value="<?php // echo $value; ?>"><?= $value ?></option> -->
        <?php // }; ?>
        </select>
    </div>
    <!-- ... 其他输入字段，如加班、缺勤等 ... -->

    <input type="submit" class="btn btn-danger form1-btn" value="Proceed">
</form>

<?php
// 假设 form3.php 接收并处理其他数据，例如：
// $payAfterAdditions = calculatePayAfterAdditions();
// $philhealth = calculatePhilhealth();
// $sss = calculateSSS();
// $totalDeductions = calculateTotalDeductions();
// $taxableSalary = calculateTaxableSalary();
// $finalTax = calculateFinalTax();
// $totalAbsences = calculateTotalAbsences();
// $basePay = getBasePay();

// 从 form2.php 接收 'month' 值
$monthDisplayed = isset($_POST['month']) ? htmlspecialchars($_POST['month']) : 'N/A';
?>

<main class="main">
    <div class="form-title">
        <p class="display-6">Employee Salary</p>
    </div>

    <div class="">
        <!-- 显示月份信息 -->
        <p>Selected Month: <?php echo $monthDisplayed; ?></p>

        <p>Pay after additions: Php <?php // echo $payAfterAdditions; ?></p>
        <p>Deductions</p>
        <p>Philhealth: Php <?php // echo $philhealth; ?></p>
        <p>SSS: Php <?php // echo $sss; ?></p>
        <p>Total deductions: Php <?php // echo $totalDeductions; ?></p>
        <p>Taxable Salary: Php <?php // echo $taxableSalary; ?></p>
        <p>Final Salary: Php <?php // echo $finalTax; ?></p>
        <!-- lalabas lang kapag december -->
        <p>13 month pay: </p> 
        <p> <?php // echo $totalAbsences; ?></p>
        <p> <?php // echo $basePay; ?></p>
    </div>
</main>

<?php
session_start(); // 启动会话

// 从 form1.php 接收 'month' 值并存储到会话
if (isset($_POST['month'])) {
    $_SESSION['month'] = htmlspecialchars($_POST['month']);
}

// ... form2.php 的其他处理 ...
?>
<form action="form3.php" method="post">
    <!-- form2.php 的其他表单元素，无需隐藏月份字段 -->
    <!-- ... -->
    <input type="submit" value="Proceed">
</form>

<?php
session_start(); // 启动会话

// 从会话中获取 'month' 值
$monthDisplayed = isset($_SESSION['month']) ? htmlspecialchars($_SESSION['month']) : 'N/A';

// 使用完后可以销毁会话变量或整个会话
// unset($_SESSION['month']); // 销毁单个会话变量
// session_destroy(); // 销毁所有会话数据

// ... form3.php 的其他处理和显示 ...
?>
<p>Selected Month (from Session): <?php echo $monthDisplayed; ?></p>