Ajax POST FormData not defined

For some reason when i use this code in my wordpress site (localhost) it throws an ‘no index defined’ error, yet when i test it in a non-wordpress environment, the ‘cvfiles’ is defined and all functions work and run as expected.
Any thoughts as to why? code below from localhost:-

// detect file upload type
    $('#cvfiles').change(function(event) {
        var uploadData = $(this).val();
        var extType = uploadData.split('.').pop();

            if (extType == "txt") {
                console.log('txt file found');
                readBlobTxt();
            } else if (extType == "docx") {

                    data = new FormData();
                    data.append( 'cvfiles', $( '#cvfiles' )[0].files[0] );

                    $.ajax({
                    url: "https://localhost/wp/wp-content/themes/twentyfourteen/inc/ajax_php_file_rename.php", // Url to which the request is send
                    type: "POST",             // Type of request to be send, called as method
                    data: data,
                    contentType: false,       // The content type used when sending data to the server.
                    cache: false,             // To unable request pages to be cached
                    processData:false,        // To send DOMDocument or non processed data file it is set to false
                    success: function(data)   // A function to be called if request succeeds
                    {
                    console.log(FormData);
                    console.log('success');
                        // run scan function file 

                                        var fileLocal = 'https://localhost/wp/wp-content/themes/twentyfourteen/inc/uploads/' + uploadData;
                                        $.get('readfile.php?fileUrl=' + fileLocal, function(data) {
                                        console.log('Load was performed.');
                                        document.getElementById('cv-content').textContent = data;
                                        scanPortfolioDocX();
                                        }); 

                    }
                    });	

            } else if (extType == "doc") {

                // stuff here

            } else if (extType == "pdf") {

                // stuff here

            } else {
                console.log('other file found');
            }

      });

ajax_php_file_rename code below:-

<?php

    $UploadDirectory    = 'https://localhost/wp/wp-content/themes/twentyfourteen/inc/uploads/'; // upload directory

    $File_Name          = strtolower($_FILES['cvfiles']['name']);
    $FileName_No_Ext    = var_dump(basename($File_Name, '.docx'));
    $File_Ext           = substr($File_Name, strrpos($File_Name, '.')); //get file extention
    $Random_Number      = rand(0, 9999999999); //Random number to be added to name.
    $NewFileName        = $FileName_No_Ext.$Random_Number.$File_Ext; //new file name

    if(move_uploaded_file($_FILES['cvfiles']['tmp_name'], $UploadDirectory.$File_Name ))
       {
        // do other stuff
        die('Success! File Uploaded.');

    }else{
        die('error uploading File!');
    }

?>

sorry cant add a link as site is still on localhost.
Thanks