var formData = new FormData();
var fili = document.getElementById( divID ).files.length;
for (var x = 0; x < fili; x++) { formData.append( "fii" , $("#"+divID).prop("files")[x]); }

var xhr = new XMLHttpRequest(); xhr.open("POST", "/uboxhr.php", true);
xhr.setRequestHeader("Content-Type", "application/x-www-form-urlencoded");
xhr.send(formData);

var_dump($_POST); // -->> I GET stuff like FULL RAW encoded 1�UV[(�c2����
var_dump($_FILES); // -->> Is EMPTY

xhr.setRequestHeader('Content-type', 'multipart/form-data');

var_dump($_FILES['fii']);