如何从HTML向PHP传递表单值并实现贷款利息、总额及月供计算？

Here's the completed PHP code that implements your loan calculation logic, along with key improvements to handle data processing and formatting:

<!doctype html>
<html lang="en">
<head><title>Registration Form</title>
<style>
.Cn{ text-align:center; color:#1e90ff; font-family:Arial, Helvetica, sans-serif; }
.add{ color:black; font-family:Arial, Helvetica, sans-serif; }
.h1{ text-align:center; color:black; font-family:Arial, Helvetica, sans-serif; }
table, th, td { border: 1px solid black; align:center; }
table.center{ margin-left:auto; margin-right:auto; }
table { border-collapse: collapse; }
</style>
</head>
<body>
<h2 class="Cn">Loan</h2>
<center class="add">blah City<br> Mobile Number: 12345678900 <br> Telephone:(08)9999999 </center>
<hr style="Width:100%;color:#dc143c">
<h1 class="h1">Loan Information</h1>

<?php
// Process form data only if form was submitted
if ($_SERVER['REQUEST_METHOD'] === 'POST') {
    // Extract and clean loan amount from radio button value
    $amount_str = $_POST['r1'] ?? '';
    $loan_amount = (float)str_replace(['Php ', ','], '', $amount_str);
    
    // Extract number of months from payment terms
    $terms_str = $_POST['r2'] ?? '';
    $months = (int)trim(str_replace('months', '', $terms_str));
    
    // Determine interest rate based on cooperative officer checkbox
    $is_cooperative = isset($_POST['chckbx']);
    $interest_rate = $is_cooperative ? 0.05 : 0.10;
    
    // Calculate loan values
    $interest = $loan_amount * $interest_rate;
    $total_amount = $loan_amount + $interest;
    $monthly_dues = $months > 0 ? $total_amount / $months : 0;
}
?>

<table class="center">
<tr><td>Date</td>
<td><?php echo date('F d, Y'); ?></td>
</tr>
<tr>
<td>Name</td>
<td><?php echo $_POST["name"] ?? '';?></td>
</tr>
<tr>
<td>Address</td>
<td><?php echo $_POST["address"] ?? '';?></td>
</tr>
<tr>
<td>Contact</td>
<td><?php echo $_POST["contact"] ?? ''; ?></td>
</tr>
<tr>
<td>Amount</td>
<td><?php echo $_POST['r1'] ?? ''; ?></td>
</tr>
<tr>
<td>Terms of Payment</td>
<td><?php echo $_POST['r2'] ?? ''; ?></td>
</tr>
<tr>
<td>Interest (<?php echo isset($is_cooperative) ? ($is_cooperative ? '5%' : '10%') : ''; ?>)</td>
<td><?php echo isset($interest) ? 'Php ' . number_format($interest, 2) : ''; ?></td>
</tr>
<tr>
<td>Total Amount</td>
<td><?php echo isset($total_amount) ? 'Php ' . number_format($total_amount, 2) : ''; ?></td>
</tr>
<tr>
<td>Monthly Dues</td>
<td><?php echo isset($monthly_dues) ? 'Php ' . number_format($monthly_dues, 2) : ''; ?></td>
</tr>
</table>
<center>
<input type="button" value="Back" onclick="window.history.back();">
</center>
</body>
</html>

Key Changes Explained: #

• Data Cleaning: Converted the loan amount string (like "Php 5,000") to a numeric value by removing non-digit characters, which is necessary for calculations.
• Interest Rate Logic: Checked if the "Cooperative Officer" checkbox is selected to apply either 5% or 10% interest rate.
• Calculations: Computed interest, total loan amount, and monthly dues using the cleaned numeric values.
• Formatting: Used number_format() to display currency values with 2 decimal places, matching the input style.
• Error Prevention: Added null coalescing operators (??) to handle cases where form fields might not be submitted, and wrapped calculations in a POST request check.
• Back Button: Replaced the submit button with a button that uses window.history.back() to navigate to the previous form page without resubmitting data.

内容的提问来源于stack exchange，提问作者rikardo14