PHP 联系页面 – 如何指定输入字段的最小字母

Question

我的实时网站上有一个 contact.php 页面，但即使访问者在姓名、电子邮件或消息字段中输入了不完整的文本，表单也会认为它们是正确的并显示成功消息。

我如何指定名称必须至少有 6 个字母、电子邮件必须有 @ 符号和正确的 .com、.org 等结尾；消息长度必须至少为 20 个字母。

PHP脚本

<?php

if ($_POST['submit']) {

  if (!$_POST['firstname']) {
    $error="<br/>- Please enter your first name";
  }
  
  if (!$_POST['lastname']) {
    $error="<br/>- Please enter your last name";
  }

  if (!$_POST['email']) {
    $error.="<br/>- Please enter your email";
  }
  if (!$_POST['message']) {
    $error.="<br/>- Please enter a message";
  }
  if (!$_POST['check']) {
    $error.="<br/>- Please confirm you are human";
  }
  
  if ($error) {
    $result='<div class="alert alert-danger" role="alert">
    <strong>Whoops, there is an error</strong>. Please correct the following: '.$error.'</div>';
  } else {
    mail("myname@mywebsite.com", 
   "Contact message", 
    "Name: ".$_POST['name']."
    Email: ".$_POST['name']."
    Message: ".$_POST['message']);
    
    {
    $result='<div class="alert alert-success" role="alert">Thank you, I\'ll be in touch shortly. </div>';
    }
  }
}
?>

#HTML CODE#

  <form method="post" role="form">
            <div class="row">
            <div class="col-md-3"></div>
                  <div class="contact-icon">
                      <i class="fas fa-user"></i>
                  </div>

                  <div class="form-inline">
                    <div class="col-md-9 form-group">
                          <label for="name">your name</label>
                          <span class="fieldSpan">
                          <input type="text" 
                          name="name" 
                          id="input-field-name"
                          class="form-control" 
                          placeholder="your name" 
                          value="<?php echo $_POST['name']; ?>"> 
                    </div>
                </div>
            </div>

        <div class="row">
        <div class="col-md-3"></div>
              <div class="contact-icon">
                <i class="fas fa-envelope"></i>
              </div>

              <div class="form-inline">
              <div class="col-md-9 form-group">
                      <label for="email">your email address</label>
                      <span class="fieldSpan">
                      <input type="email" 
                      name="email" 
                      id="input-field-email"
                      class="form-control" 
                      placeholder="yourname@website.com" 
                      value="<?php echo $_POST['email']; ?>">
                  </div>
                </div>
         </div>

        <div class="row">
        <div class="col-md-3"></div>
              <div class="contact-icon">
                  <i class="fas fa-pencil-alt"></i>
              </div>
        
              <div class="form-inline">
                 <div class="col-md-9 form-group">
                        <label for="message">your message</label>
                        <span class="fieldSpan vertical-align:top">
                        <textarea name="message" 
                        rows="5" 
                        id="input-field-message"
                        class="form-control" 
                        placeholder="your message">
                        <?php echo $_POST['message']; ?></textarea>
                        <br>
                        <br>
                    </div>
                    </div>
              </div>
        </div>
 

              <div class="col-md-12">
                 <div class="checkbox">
                    <label>
                        <input type="checkbox" 
                        name="check"> 
                        Check this box if you're human.
                      </label>
                  </div>
              </div>
        </div>

      <div class="col-md-3"></div>
      <div class="row">
          <div class="col-md-9">
              <input type="submit" 
              name="submit" 
              class="btn btn-secondary" 
              value="send message"/>
            </div> 
        </div>

     </form>
      
     </div>
      </div>
    </div>
  </section>
  

 <!-- ----------- SCRIPTS------------ -->

    <script src="https://code.jquery.com/jquery-3.3.1.slim.min.js" integrity="sha384-q8i/X+965DzO0rT7abK41JStQIAqVgRVzpbzo5smXKp4YfRvH+8abtTE1Pi6jizo" crossorigin="anonymous"></script>

<script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.14.3/umd/popper.min.js" integrity="sha384-ZMP7rVo3mIykV+2+9J3UJ46jBk0WLaUAdn689aCwoqbBJiSnjAK/l8WvCWPIPm49" crossorigin="anonymous"></script>

<script src="https://stackpath.bootstrapcdn.com/bootstrap/4.1.3/js/bootstrap.min.js" integrity="sha384-ChfqqxuZUCnJSK3+MXmPNIyE6ZbWh2IMqE241rYiqJxyMiZ6OW/JmZQ5stwEULTy" crossorigin="anonymous"></script>

Answer 1

https://www.w3schools.com/php/php_form_url_email.asp

嘿！这有你要找的答案。这是一个叫做输入验证的概念，每种语言都有自己的处理方式。

下面是 link 的摘录，验证了一些所需的字段。

<?php
// define variables and set to empty values
$nameErr = $emailErr = $genderErr = $websiteErr = "";
$name = $email = $gender = $comment = $website = "";

if ($_SERVER["REQUEST_METHOD"] == "POST") {
  if (empty($_POST["name"])) {
    $nameErr = "Name is required";
  } else {
    $name = test_input($_POST["name"]);
    // check if name only contains letters and whitespace
    if (!preg_match("/^[a-zA-Z ]*$/",$name)) {
      $nameErr = "Only letters and white space allowed"; 
    }
  }

  if (empty($_POST["email"])) {
    $emailErr = "Email is required";
  } else {
    $email = test_input($_POST["email"]);
    // check if e-mail address is well-formed
    if (!filter_var($email, FILTER_VALIDATE_EMAIL)) {
      $emailErr = "Invalid email format"; 
    }
  }

  if (empty($_POST["website"])) {
    $website = "";
  } else {
    $website = test_input($_POST["website"]);
    // check if URL address syntax is valid (this regular expression also allows dashes in the URL)
    if (!preg_match("/\b(?:(?:https?|ftp):\/\/|www\.)[-a-z0-9+&@#\/%?=~_|!:,.;]*[-a-z0-9+&@#\/%=~_|]/i",$website)) {
      $websiteErr = "Invalid URL"; 
    }
  }

  if (empty($_POST["comment"])) {
    $comment = "";
  } else {
    $comment = test_input($_POST["comment"]);
  }

  if (empty($_POST["gender"])) {
    $genderErr = "Gender is required";
  } else {
    $gender = test_input($_POST["gender"]);
  }
}
?>

您可以通过诸如在 if 语句中检查名称字段的长度是否大于或等于 6 等方式来控制您需要的验证类型，确保该字段不为空。

Answer 2

您可以直接使用 html 功能来做到这一点。

最小长度特征已在 post 中得到解答：minlength 如果您在 html 中使用电子邮件输入元素，浏览器将自动验证。

PHP 联系页面 – 如何指定输入字段的最小字母

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