史蒂夫问，我有一个联系表单组件： 

class Contact extends React.Component {
  constructor(props) {
    super(props);
    this.state = {
      name: '',
      email: '',
      message: ''
    }
  }

  render() {
    return (
      <>
        <Helmet>
          <title>Title</title>
        </Helmet>
        <h2>Contact</h2>
        <form id="contact-form" onSubmit={this.handleSubmit.bind(this)} method="POST">
          <div className="form-group">
              <input type="text" className="form-control" placeholder="Name" />
          </div>
          <div className="form-group">
              <input type="email" className="form-control" aria-describedby="emailHelp" placeholder="Email" />
          </div>
          <div className="form-group">
              <textarea className="form-control" rows="5" placeholder="Message"  ></textarea>
          </div>
          <button type="submit" className="btn btn-primary">Submit</button>
        </form>
      </>
    )
  }

  onNameChange(event) {
    this.setState({name: event.target.value})
  }

  onEmailChange(event) {
    this.setState({email: event.target.value})
  }

  onMessageChange(event) {
    this.setState({message: event.target.value})
  }

  handleSubmit(e) {
    e.preventDefault();
  
    fetch('/mail.php', {
        method: "POST",
        body: JSON.stringify(this.state),
        headers: {
          'Accept': 'application/json',
          'Content-Type': 'application/json'
        },
      }).then(
      (response) => (response.json())
        ).then((response)=> {
      if (response.status === 'success') {
        alert("Message Sent."); 
        this.resetForm()
      } else if(response.status === 'fail') {
        alert("Message failed to send.")
      }
    })
  }

提交联系表单时，我收到一个后台返回的错误 Message failed to send.

该文件mail.php位于的根目录中public_html。该文件与案例相同，并且包含： 

<?php
header("Access-Control-Allow-Origin: *");
header("Access-Control-Allow-Headers: Content-Type");
header("Content-Type: application/json");

$rest_json = file_get_contents("php://input");
$_POST = json_decode($rest_json, true);

$errors = array();
if ($_SERVER['REQUEST_METHOD'] === "POST") {
  if (empty($_POST['email'])) {
    $errors[] = 'Email is empty';
  } else {
    $email = $_POST['email'];
    
    // validating the email
    if (!filter_var($email, FILTER_VALIDATE_EMAIL)) {
        $errors[] = 'Invalid email';
    }
  }
  if (empty($_POST['message'])) {
    $errors[] = 'Message is empty';
  } else {
    $message = $_POST['message'];
  }
  if (empty($errors)) {
    $date = date('j, F Y h:i A');
    
    $emailBody = "
    <html>
    <head>
    <title>$email is contacting you</title>
    </head>
    <body style=\"background-color:#fafafa;\">
    <div style=\"padding:20px;\">
    Date: <span style=\"color:#888\">$date</span>
    <br>
    Email: <span style=\"color:#888\">$email</span>
    <br>
    Message: <div style=\"color:#888\">$message</div>
    </div>
    </body>
    </html>
    ";
    
    $headers =  'From: Contact Form <contact@mydomain.com>' . "\r\n" .
    "Reply-To: $email" . "\r\n" .
    "MIME-Version: 1.0\r\n" . 
    "Content-Type: text/html; charset=iso-8859-1\r\n";

    $to = 'contact@example.com';
    $subject = 'Contacting you';
    
    if (mail($to, $subject, $emailBody, $headers)) {
      $sent = true; 
    }
  }
}
?>

  <?php if (!empty($errors)) : ?> 

{
  "status": "fail",
  "error":  <?php echo json_encode($errors) ?>
}
  <?php endif; ?>
  
  
  <?php if (isset($sent) && $sent === true) : ?> 

{
  "status": "success",
  "message": "Your data was successfully submitted"
}
  <?php endif; ?>


有人能帮我确定为什么提交的表给未成功发送电子邮件吗？


密码猴子的回答

根据案例，应该控制您的输入元素（即应该为值prop分配一个状态变量），并onChange附加一个事件： 

<div className="form-group">
            <label htmlFor="name">Name</label>
            <input type="text" className="form-control" value={this.state.name} onChange={this.onNameChange.bind(this)} />
          </div>
          <div className="form-group">
            <label htmlFor="exampleInputEmail1">Email address</label>
            <input type="email" className="form-control" aria-describedby="emailHelp" value={this.state.email} onChange={this.onEmailChange.bind(this)} />
          </div>
          <div className="form-group">
            <label htmlFor="message">Message</label>
            <textarea className="form-control" rows="5" value={this.state.message} onChange={this.onMessageChange.bind(this)} />
</div>
其他状态未更新，您的提交将空字段发送到您的php文件。