PHP - Multipart Form Won't Post When Multiple Type=input Elements Are Defined

I am having trouble with passing values with a POST to another php file.  I am getting the error :  undefined index : productID and undefined index: filename.  I have also tried :  <form   method = \"POST?pdib=$processID&filename=$filename\" action = \"upload2.php\"  >  When I look at the array of superglobals, they are both defined.  Thank you! 

 Here is the code :

drawfirsttwoforms:

$sql = "SELECT ProductFilename, ProductName, ProductID, ProductDescription,ProductCost,ProductQuantity, ProductCatTitle FROM products 
INNER JOIN customers ON customers.CustomerID = products.CustomerID 
WHERE ((products.ProductKeyWord1 = ?) 
OR (products.ProductKeyWord2 = ?) OR (products.ProductKeyWord3 = ? ))  AND (products.ProductCatTitle = ?) ";

$stmt = $dbo->prepare($sql);
$stmt->bindParam(1, $keyword1);
$stmt->bindParam(2, $keyword1);
$stmt->bindParam(3, $keyword1);
$stmt->bindParam(4, $titleOfSelectedDropDown);

$stmt->execute();

while ($row = $stmt->fetch()) {

//these variables do have values here
$productID = $row['ProductID'];
$filename = $row['ProductFilename'];

$string1 .=  "  
<div  class = \"A\" id = \"$mainDiv\">
<p id = \"link1\">product id   :$productID</p>
<p>category id  :$category</p>
<div class = \"A\" id = \"endz\"></div>
<div class = \"A\" id = \"startz\"></div>
<div class=\"container\">
<div id = \"testing\" >testing <div>
<div id = \"$displayID\" >  </div>
<div class=\"row\" >
<div class=\"col\">
	
	<form   method = \"POST\" action = \"upload2.php\"  >
      
      
    
	<input type=hidden id='$productID' name= '$productID' value=\"A\">
	<input type=hidden id=\"$filename\" name=$filename value=\"B\">
	
      
      
      <button value = \"Submit\" type = \"submit\"  >submit it</button>
	</form>
	<iframe id=\"upload_target\" name=\"upload_target\"  style=\"width:0;height:0;border:0px solid #fff;\"></iframe> 
	<img width=\"120\" height =\"120\"  id = \"$imageID\"  src=\"../php proj/uploads/$filename?<?php echo filemtime($filename)?>\">
	<button    onclick = \"imageRefresh( '{$filename}', '{$imageID}', '{$_SESSION["msg"]}' )\" >Display</button>
	</div>


AFTER:
  

if (!isset($myObj) && isset($string1))
{
$myObj = new stdClass();
$myObj->htmlstuff = $string1;


//Encode the data as a JSON string
$jsonStr = json_encode($myObj);
echo $jsonStr;
}

function printHTML1(keyword){ 
	
	
	const element = document.getElementById("dropDown1");
		
	//const checkValue = element.options[element.selectedIndex].value;
	const checkText = element.options[element.selectedIndex].text;
	
	var val1 = checkText;

	var xmlhttp = new XMLHttpRequest();
	
	
	var keyword1 = keyword;
	var url = "drawfirsttwoforms.php?keyword=" + keyword.value + "&" + "val1=" + val1;
	


	xmlhttp.onreadystatechange = function() {
		
	if (this.readyState == 4 && this.status == 200) {
		
		
		var jsonData = JSON.parse(this.responseText);
		var answerHtml = jsonData.htmlstuff;
		document.getElementById("codehere").innerHTML = answerHtml;

		createAndModifyDivs();


		}
	};
	
	xmlhttp.open("GET", url , true);
	
	xmlhttp.send();
	
	
}

upload2.php


<?php
session_start();
$productID = $_POST['productID'];
$filename = $_POST['filename'];

Can anyone let me know what I am doing wrong.  I am sure it will (after the fact) be obvious, but I don't see it right now.  Wish to remove all array elements which do not implement ValidatorCallbackInterface.  Thanks

<?php
interface ValidatorCallbackInterface{}
class ValidatorCallback implements ValidatorCallbackInterface{}

function array_filter_recursive($input) {
    foreach ($input as &$value) {
        if (is_array($value)) {
            $value = array_filter_recursive($value);
        }
    }
    return array_filter($input, function($v) {
        return $v instanceOf ValidatorCallbackInterface;
    });
}

function recursive_unset(&$array) {
    foreach ($array as $key => $value) {
        if (is_array($value)) {
            recursive_unset($value);
            if(empty($value)) {
                unset($array[$key]);
            }
        }
        elseif(!$value instanceOf ValidatorCallbackInterface) {
            unset($array[$key]);
        }
    }
}

$validatorCallback = new ValidatorCallback();
$rules=[
    'callbackId'=>"integer",
    'info'=>[
        'arrayofobjects'=>[$validatorCallback],
        'foo1'=>'bar1'
    ],
    'foo2'=>'bar2',
    'bla'=>[
        'a'=>'aa',
        'b'=>'bb',
    ],
    'singleobject'=>$validatorCallback
];

echo('original rules'.PHP_EOL);
var_dump($rules);

$desiredrules=[
    'info'=>[
        'arrayofobjects'=>[$validatorCallback]
    ],
    'singleobject'=>$validatorCallback
];

echo('desired rules'.PHP_EOL);
var_dump($desiredrules);

echo('array_filter_recursive'.PHP_EOL);
var_dump(array_filter_recursive($rules));

echo('recursive_unset'.PHP_EOL);
recursive_unset($rules);
var_dump($rules);

original rules
array(5) {
  ["callbackId"]=>
  string(7) "integer"
  ["info"]=>
  array(2) {
    ["arrayofobjects"]=>
    array(1) {
      [0]=>
      object(ValidatorCallback)#1 (0) {
      }
    }
    ["foo1"]=>
    string(4) "bar1"
  }
  ["foo2"]=>
  string(4) "bar2"
  ["bla"]=>
  array(2) {
    ["a"]=>
    string(2) "aa"
    ["b"]=>
    string(2) "bb"
  }
  ["singleobject"]=>
  object(ValidatorCallback)#1 (0) {
  }
}
desired rules
array(2) {
  ["info"]=>
  array(1) {
    ["arrayofobjects"]=>
    array(1) {
      [0]=>
      object(ValidatorCallback)#1 (0) {
      }
    }
  }
  ["singleobject"]=>
  object(ValidatorCallback)#1 (0) {
  }
}
array_filter_recursive
array(1) {
  ["singleobject"]=>
  object(ValidatorCallback)#1 (0) {
  }
}
recursive_unset
array(2) {
  ["info"]=>
  array(2) {
    ["arrayofobjects"]=>
    array(1) {
      [0]=>
      object(ValidatorCallback)#1 (0) {
      }
    }
    ["foo1"]=>
    string(4) "bar1"
  }
  ["singleobject"]=>
  object(ValidatorCallback)#1 (0) {
  }
}

0: {dogidindatabase: "9892", value: "Excalibur Khali des Gardiens de la Cour ",…}
dogidindatabase: "9892"
label: "<img src='../main/img/female.png' height='20'>Excalibur Khali des Gardiens de la Cour   "
value: "Excalibur Khali des Gardiens de la Cour   "
1: {dogidindatabase: "15942", value: "Excalibur from Bandit's World Kalli",…}
dogidindatabase: "15942"
label: "<img src='../main/img/male.png' height='20'>Excalibur from Bandit's World   Kalli"
value: "Excalibur from Bandit's World   Kalli"

<script type='text/javascript'>
		//<![CDATA[
		$(function() {
		
				$(".dog").autocomplete({
				source: "xxx.php",
				minLength: 3,
				select: function(event, ui) {
					$('#dogidindatabase').val(ui.item.dogidindatabase);
					}
			});
			
			$["ui"]["autocomplete"].prototype["_renderItem"] = function( ul, item) {
				return $( "<li></li>" ) 
  				.data( "item.autocomplete", item )
  				.append( $( "<a></a>" ).html( item.label ) )
  				.appendTo( ul );
			};
	
		});
		//]]>
</script>

<input type='text' name='dog' class='dog' value='".strip_tags(${'dogname' .($countbabymale+1)})."' size='35' data-required='true' /><br>
	
<input class='readonly' readonly='readonly' type='text' id='dogidindatabase' name='dogidindatabase' size='5'  />