使用JS的FormData类将多个字段的数据插入数据库表？

Question

我需要使用ajax和FormData类将数据插入MySql数据库表中。通过使用jquery为许多<input>声明许多变量，然后将这些变量放入if-else语法中进行检查，可以轻松解决此问题。但是我需要使用FormData类JavaScript，然后将代码分布在3个文件中：

action_project.php

<?php
  require_once("../config.php");
  include(CLASSES_PATH.DS.'project.php');

$objProject = new Project();

if(isset($_POST)) {

$product            = isset($_POST['product'])?$_POST['product']:'';
$customer           = isset($_POST['cutomer'])?$_POST['cutomer']:'';
echo $objProject->AddProject($customer,$product);
?>

project.php

 class Project
 {
private $mysqli_lib;

function __construct()
{
    global $obj_mysql;
    $this->mysqli_lib = $obj_mysql;
}


function AddProject($customer,$product)
{
    $query = "INSERT INTO tbl_project_detail(customer,product) VALUES ('$customer','$product')";
     $response = $this->mysqli_lib->insert($query);
    return $response > 0 ? "success" : "fail";
}
}

project_view.php （为清楚起见，我删除了一些html元素标签）

  <form method="post" class="form-horizontal" id="fieldsform" enctype="multipart/form-data" action="" style="clear:both">
    <input type="text" class="form-control" name="product" value="product" 
   id="product">
 <input type="text" class="form-control" name="customer" value="customer" 
   id="product">
  <button type="submit" class="btn btn-primary" name="btnQuoSave" id 
    ="btnQuoSave">Save</button>
  </form>
      <script type="text/javascript">
       $(document).ready(function() {

    $(document).on('click', '#btnQuoSave', function () {

        var formdata = new FormData($('#fieldsform')); //I need to figure out this line of code to work, i think.

        $.ajax({
            type: "POST",
            url: "../includes/ajax/action_project.php",
            async: true,
            contentType: false,
            processData: false,
            cache: false,
            data: formdata,

            success: function(data){
            data = data.trim();
            //console.log(data);
            //alert(data);

            if(data == 'success'){
             alert('sucess');

            }else if(data == 'fail'){
                alert('fail');
              }

           }

    });

     });  
  });

所以我的任务是如何使用ajax和FormData类将数据插入MySql数据库表中？