Inserting data using checkbox - PDO

I have checkbox, that who is checked. That's will be inserted in my table:inclusion. I want to insert data, using checkbox with other textbox, but I don't have any idea for inserting data using checkbox, please help me out of this problem! Tyia!

Error: Invalid argument supplied for each()

Here's my code:

//script
 $(document).on('submit', '#user_form', function(event){
  event.preventDefault();
  var roomname = $('#text_name').val();
  var id = [];  
   $(':checkbox:checked').each(function(i){
    id[i] = $(this).val();
   });
  if(roomname != '')
  {
   $.ajax({
    url:"insert.php",
    method:'POST',
    data:new FormData(this),
    // data: {inclusion_name:inclusion_name},
    contentType:false,
    processData:false,
    success:function(data)
    {
     alert(data);
     $('#user_form')[0].reset();
     $('#userModal').modal('hide');
     dataTable.ajax.reload();
    }
   });
  }
  else
  {
   alert("Both Fields are Required");
  }
 });

insert.php

$statement = $connection->prepare("
   INSERT INTO rooms (roomname) 
   VALUES (:text_name)
  ");
  $result = $statement->execute(
   array(
    ':text_name' => $_POST["text_name"]
   )
  );

foreach($_POST["id"] as $id)
 {
  $statement = $connection->prepare("
   INSERT INTO inclusion (inclusion) 
   VALUES (:id)
  ");

  $result = $statement->execute(
   array(
    ':id' => $_POST["id"]
   )
  );
 }