File upload with form inputs AJAX not working - php

Question

I've been searching for solutions across SO and have tried them, but not one of the answers I found has solved my problem. So here is it.
I am working on a simple web app with input details and file upload (.docx files). I used FormData for the handling of form data, but the server-side operation only works for the form inputs like text, password, date ,etc.
This is my JS code; the commented lines are the one which I attempted but did not work.
var myForm = $("#add-thesis-form");
var formData = new FormData(myForm);
//var formData = myForm.serialize();
$.ajax({
type: "POST" ,
url: "thesis-scripts/add_thesis.php",
data: formData
// processData: false,
// contentType: false
}).done(function(data){
$('#addThesisModal').modal('hide');
alert(data);
//alert("Successfully saved a record to the database. ");
showThesis();
});
My PHP code (using Meekro DB)
$title = $_POST["title"];
$description = $_POST["description"];
$categoryId = $_POST["category_id"];
$collegeId = $_POST["college_id"];
$departmentId = $_POST["department_id"];
$uploadedBy = $_SESSION["user"];
$uploadedAt = DB::queryFirstField("SELECT NOW();");
$year = $_POST["thesis_year"];
$keywords = $_POST["keywords"];
$authors = $_POST["authors"];
//FILE UPLOAD
$targ_dir = "../uploads/";
$targ_file = $targ_dir . basename($_FILES["thesis"]["name"]);
$flagOk = 1;
$tempFolder = $_FILES["thesis"]["tmp_name"];
move_uploaded_file($tempFolder, $targ_file);
//!FILE UPLOAD
$result = DB::insert('theses', array(
"title" => $title,
"description" => $description,
"categoryId" => $categoryId,
"collegeId" => $collegeId,
"departmentId" => $departmentId,
"uploadedBy" => $uploadedBy,
"uploadedAt" => $uploadedAt,
"pubyear" => $year,
"filepath" => $targ_file,
"views" => 0,
"rating" => 0,
"keywords" => $keywords,
"authors" => $authors
));
I've tried a print_r($_FILES) and that one works, but this one doesn't. Please help me. Thanks.
Setting the contentType:false causes the server to throw an error Undefined index on all the $_POST variables.

Answer 1

Maybe your form should includes enctype="multipart/form-data"
Maybe this would work :
$.ajax({
type: "POST" ,
url: "thesis-scripts/add_thesis.php",
data: "multipart/form-data"
...