联系表单不起作用(Php 端）

我想为我的网站制作一个联系表格，我正在关注这篇博文，但使其更简单（需要姓名、地址、消息）。

我正在我的机器上的本地主机上托管文件以执行 php。我认为我在 php 代码中有错误，但无法找到它。

<script src="//ajax.googleapis.com/ajax/libs/jquery/1.11.1/jquery.min.js"></script>
    <script type="text/javascript">
    $(document).ready(function() {
    $("#submit_btn").click(function() { 
        var proceed = true;
        //simple validation at client's end
        //loop through each field and we simply change border color to red for invalid fields       
        $("#contact_form input[required=true], #contact_form textarea[required=true]").each(function(){
            $(this).css('border-color',''); 
            if(!$.trim($(this).val())){ //if this field is empty 
                $(this).css('border-color','red'); //change border color to red   
                proceed = false; //set do not proceed flag
            }
            //check invalid email
            var email_reg = /^(['w-'.]+@(['w-]+'.)+['w-]{2,4})?$/; 
            if($(this).attr("type")=="email" && !email_reg.test($.trim($(this).val()))){
                $(this).css('border-color','red'); //change border color to red   
                proceed = false; //set do not proceed flag              
            }   
        });
        if(proceed) //everything looks good! proceed...
        {
            //get input field values data to be sent to server
            post_data = {
                'user_name'     : $('input[name=name]').val(), 
                'user_email'    : $('input[name=email]').val(), 
                'msg'           : $('textarea[name=message]').val()
            };
            console.log(post_data)
            //Ajax post data to server
            $.post('php/contact_me.php', post_data, function(response){  
                console.log(response)
                if(response.type == 'error'){ //load json data from server and output message     
                    output = '<div class="error">'+response.text+'</div>';
                }else{
                    // output = '<div class="success">'+response.text+'</div>';
                    //reset values in all input fields
                    // $("#contact_form  input[required=true], #contact_form textarea[required=true]").val(''); 
                    // $("#contact_form #contact_body").slideUp(); //hide form after success
                }
                // $("#contact_form #contact_results").hide().html(output).slideDown();
            }, 'json');
        }
    });

PHP 文件：

<?php
if($_POST)
{
    $to_email       = "test@gmail.com"; //Recipient email, Replace with own email here
    //check if its an ajax request, exit if not
    if(!isset($_SERVER['HTTP_X_REQUESTED_WITH']) AND strtolower($_SERVER['HTTP_X_REQUESTED_WITH']) != 'xmlhttprequest') {
        $output = json_encode(array( //create JSON data
            'type'=>'error', 
            'text' => 'Sorry Request must be Ajax POST'
        ));
        die($output); //exit script outputting json data
    } 
    //Sanitize input data using PHP filter_var().
    $user_name      = filter_var($_POST["user_name"], FILTER_SANITIZE_STRING);
    $user_email     = filter_var($_POST["user_email"], FILTER_SANITIZE_EMAIL);
    $message        = filter_var($_POST["msg"], FILTER_SANITIZE_STRING);
    //additional php validation
    if(strlen($user_name)<4){ // If length is less than 4 it will output JSON error.
        $output = json_encode(array('type'=>'error', 'text' => 'Name is too short or empty!'));
        die($output);
    }
    if(!filter_var($user_email, FILTER_VALIDATE_EMAIL)){ //email validation
        $output = json_encode(array('type'=>'error', 'text' => 'Please enter a valid email!'));
        die($output);
    }
    if(strlen($message)<3){ //check emtpy message
        $output = json_encode(array('type'=>'error', 'text' => 'Too short message! Please enter something.'));
        die($output);
    }
    //email body
    $message_body = $message."'r'n'r'n-".$user_name."'r'nEmail : ".$user_email ;
    //proceed with PHP email.
    $headers = 'From: '.$user_name.'' . "'r'n" .
    'Reply-To: '.$user_email.'' . "'r'n" .
    'X-Mailer: PHP/' . phpversion();
    $send_mail = mail($to_email, $subject, $message_body, $headers);
    if(!$send_mail)
    {
        //If mail couldn't be sent output error. Check your PHP email configuration (if it ever happens)
        $output = json_encode(array('type'=>'error', 'text' => 'Could not send mail!'));
        die($output);
    }else{
        $output = json_encode(array('type'=>'message', 'text' => 'Hi '.$user_name .' Thank you for your email'));
        die($output);
    }
}
?>