Ajax - 响应始终为 0

Question

我正在尝试访问“Contactus.php”，但它没有..

输出总是“Invalid Credentials！” 我试图在第一个 php 中显示警报以确保调用了 php 代码但它也没有显示任何内容

那么，我该怎么做才能解决这个问题..

有代码..

JQuery 代码：

<script>
    $(document).ready(function(){
        $('#contact').submit(function(e){
           var data=$("#contact").serialize();
           e.preventDefault();
                $.ajax({
                type: "POST",
                url: 'PHP/Contactus.php',
                data: data,
                success: function(response) {
                    if (response == "1")
                    {
                        alert('Success');
                    }
                    else
                    {
                        alert('Invalid Credentials!');
                    }
                        }
                });
                                                
        });
    });
</script>

在表单之前显示错误，然后是表单..

HTML：

<?php if(!empty($errors)): ?>
                        <div class="alert alert-danger">
                            <?php foreach ($errors as $error): ?>
                                <div><?php echo $error ?></div>
                            <?php endforeach; ?>
                        </div>
                    <?php endif; ?>
                    <?php if(empty($errors)): ?>
                        <div class="alert alert-success">
                            Message Sent..
                        </div>
                    <?php endif; ?>

<form id="contact" action="PHP/Contactus.php" method="POST">
                        <div class="row">
                            <div class="col-md-6 col-sm-12">
                                <fieldset>
                                    <input name="name" type="text" id="name" placeholder="Your Name*" >
                                </fieldset>
                            </div>
                            <div class="col-md-6 col-sm-12">
                                <fieldset>
                                    <input name="email" type="text" id="email" placeholder="Your Email*" >
                                </fieldset>
                            </div>
                            <div class="col-md-12 col-sm-12">
                                <fieldset>
                                    <input name="subject" type="text" id="subject" placeholder="Subject">
                                </fieldset>
                            </div>
                            <div class="col-lg-12">
                                <fieldset>
                                    <textarea name="message" rows="6" id="message" placeholder="Message" ></textarea>
                                </fieldset>
                            </div>
                            <div class="col-md-6 col-sm-12">
                                <fieldset>
                                    <button type="submit" name="Submit" id="form-submit" class="main-button">Submit Ticket</button>
                                </fieldset> 
                            </div>
                            <div class="col-md-6 col-sm-12">
                                <fieldset>
                                    <button type="submit" id="form-submit" class="main-button">Start Live Chat</button>
                                </fieldset>
                            </div>
                        </div>
                    </form>

验证表单的 PHP 代码..

PHP 代码：

<?php
echo "<script>alert('I'm here');</script>";
if (isset($_POST['name']) && $_POST['name'] && isset($_POST['email']) && $_POST['email']
&& isset($_POST['subject']) && $_POST['subject'] && isset($_POST['message']) && $_POST['message'])
 {
     $errors=[];

   if(empty($_POST['name'])){
        $errors[]='Your Name is required';
    }    
     if(empty($_POST['email'])){
       $errors[]='Your Email is required';
   }else if (!filter_var($_POST['email'], FILTER_VALIDATE_EMAIL)) {
         $errors[] = "Invalid email format";
      }
        if(empty($_POST['subject'])){
           $errors[]='The Subject is required';
        }
      if(empty($_POST['message'])){
           $errors[]='The Message is required';       
          }
    
}

 
?>

警报响应后： enter image description here