Php Web表单消息出错后消失

我的网络表单工作正常，除了 如果用户提交缺少1个或多个字段的表单 用户将看到错误消息和所有输入/消息消失。 用户必须再次键入消息

1） 如何保留消息，以便用户不必再次键入

2） 我的web表单是否安全，不受垃圾邮件发送者的攻击

我的网络表单

我的表格代码：

    <?php  
 // check for a successful form post  
                if (isset($_GET['s'])) echo "<div class=\"alert alert-success\">".$_GET['s']."</div>";  

                // check for a form error  
                elseif (isset($_GET['e'])) echo "<div class=\"alert alert-danger\">".$_GET['e']."</div>";  

            ?>
      <form role="form" method="POST" action="contact-form-submission.php">
        <div class="row">
          <div class="form-group col-lg-4">
            <label for="input1">Name</label>
            <input type="text" name="contact_name" class="form-control" id="input1">
          </div>
          <div class="form-group col-lg-4">
            <label for="input2">Email Address</label>
            <input type="email" name="contact_email" class="form-control" id="input2">
          </div>
          <div class="form-group col-lg-4">
            <label for="input3">Phone Number/WhatsApp</label>
            <input type="phone" name="contact_phone" class="form-control" id="input3">
          </div>
          <div class="clearfix"></div>
          <div class="form-group col-lg-12">
            <label for="input4">Message</label>
            <textarea name="contact_message" class="form-control" rows="6" id="input4"></textarea>
          </div>
          <div class="form-group col-lg-12">
            <input type="hidden" name="save" value="contact">
            <button type="submit" class="btn btn-primary">Submit</button>
          </div>
        </div>
      </form>

my php:

    <?php

// check for form submission - if it doesn't exist then send back to contact form
if (!isset($_POST['save']) || $_POST['save'] != 'contact') {
    header('Location: contact.php'); exit;
}

// get the posted data
$name = $_POST['contact_name'];
$email_address = $_POST['contact_email'];
$phone = $_POST['contact_phone'];
$message = $_POST['contact_message'];

// check that a name was entered
if (empty($name))
    $error = 'You must enter your name.';
// check that an email address was entered
elseif (empty($email_address)) 
    $error = 'You must enter your email address.';
// check for a valid email address
elseif (!preg_match('/^[_a-z0-9-]+(\.[_a-z0-9-]+)*@[a-z0-9-]+(\.[a-z0-9-]+)*(\.[a-z]{2,3})$/', $email_address))
    $error = 'You must enter a valid email address.';
// check that a phone number was entered
if (empty($phone))
    $error = 'You must enter your phone number.';
// check that a message was entered
elseif (empty($message))
    $error = 'You must enter a message.';

// check if an error was found - if there was, send the user back to the form
if (isset($error)) {
    header('Location: contact.php?e='.urlencode($error)); exit;
}

$headers = "From: $email_address\r\n"; 
$headers .= "Reply-To: $email_address\r\n";

// write the email content
$email_content = "Name: $name\n";
$email_content .= "Email Address: $email_address\n";
$email_content .= "Phone Number: $phone\n";
$email_content .= "Message:\n\n$message";

// send the email
//ENTER YOUR INFORMATION BELOW FOR THE FORM TO WORK!
mail ('xxxx@gmail.com', 'Jewelryxxx.com Online Form', $email_content, $headers);

// send the user back to the form
header('Location:jewelry-indonesia-thankyou.html?s='.urlencode('Your Message Has Been Sent ! Thank you for your message.')); exit;

?>

名称
电子邮件地址
电话号码/WhatsApp
消息
提交
我的php：
为了避免用户在脚本跳入错误验证时不必再次键入，您可以将$\u POST字段存储到一个变量，然后在html字段值上再次调用该变量

通过放置capcha和更多验证输入，可以避免Web表单垃圾邮件发送者，如上所述，只需使用isset即可

isset（$\u POST['keterangan']）
例如

!！isset（）和$_POST[var]==“”；相同的意思

在1页代码contact.php上编辑所有进程

<?php  
$name = $_POST['contact_name'];
$email_address = $_POST['contact_email'];
$phone = $_POST['contact_phone'];
$message = $_POST['contact_message'];
 if ($name=="" || $email_address="" || $phone=="" || $message==""){
        if ($_POST['save']=="contact"){
        echo "semua field harus diisi untuk melanjutkan";
        }
    }else{
    // check that a name was entered
    if (empty($name))
        $error = 'You must enter your name.';
    // check that an email address was entered
    elseif (!isset($email_address)) 
        $error = 'You must enter your email address.';
    // check for a valid email address
    elseif (preg_match("/^[_a-z0-9-]+(\.[_a-z0-9-]+)*@[a-z0-9-]+(\.[a-z0-9-]+)*(\.[a-z]{2,3})$/", $email_address))
        $error = 'You must enter a valid email address.';
    // check that a phone number was entered
    if (empty($phone))
        $error = 'You must enter your phone number.';
    // check that a message was entered
    elseif (empty($message))
        $error = 'You must enter a message.';

    // check if an error was found - if there was, send the user back to the form
    if (isset($error)) {
    echo "<div class=\"alert alert-danger\">".$error."</div>";
    }else{
    $headers = "From: $email_address\r\n"; 
    $headers .= "Reply-To: $email_address\r\n";

    $email_content = "Name: $name\n";
    $email_content .= "Email Address: $email_address\n";
    $email_content .= "Phone Number: $phone\n";
    $email_content .= "Message:\n\n$message";

    mail ('xxxx@gmail.com', 'Jewelryxxx.com Online Form', $email_content, $headers);

    // send the user back to the form
    echo "<div class=\"alert alert-success\">Your Message Has Been Sent ! Thank you for your message.</div>";
    }
 }              
    echo '<form role="form" method="POST" action="contact.php">
        <div class="row">
          <div class="form-group col-lg-4">
            <label for="input1">Name</label>
            <input type="text" name="contact_name" class="form-control" id="input1" value="'.$name.'">
          </div>
          <div class="form-group col-lg-4">
            <label for="input2">Email Address</label>
            <input type="email" name="contact_email" class="form-control" id="input2" value="'.$email_address.'">
          </div>
          <div class="form-group col-lg-4">
            <label for="input3">Phone Number/WhatsApp</label>
            <input type="phone" name="contact_phone" class="form-control" id="input3" value="'.$phone.'">
          </div>
          <div class="clearfix"></div>
          <div class="form-group col-lg-12">
            <label for="input4">Message</label>
            <textarea name="contact_message" class="form-control" rows="6" id="input4">'.$message.'</textarea>
          </div>
          <div class="form-group col-lg-12">
            <input type="hidden" name="save" value="contact">
            <button type="submit" class="btn btn-primary">Submit</button>
          </div>
        </div>
      </form>';

?>


“1）如何保存邮件，以便用户不必再次键入？”=>使用
isset
-“2）我的web表单不受垃圾邮件发送者的攻击吗？”=>我们/我不知道，您没有提供任何代码。感谢NekoMata我的php技能很差，请给我isset的php代码。我花了几个小时试图找到要使用的php代码。terima kasih.对不起，我试过了，但不起作用，不知道为什么…在提交失败后，邮件仍然不见了