<?php


$data = array (
  'code'=> array (1,2,3),
  'name'=> array ('n1', 'n2', 'n3'),
  'type'=> array ('t1', 't2', 't3'),
  'element'=>array(array(1,2), array(3,4), array(5,6))
);

$result = array();
$keys = array_keys ($data);
foreach ($data['code'] as $i=>$code) {
  $row = array();
  foreach ($keys as $key)
    $row[$key] = $data[$key][$i];
  $result[] = $row;
}

print_r ($result);
echo json_encode ($result);