Ajax modal form with select2

Hi,

I'm using Select2 on all regular form PHP page and this is working ok.

I need to add a select2 field to an existing ajax form which is a modal php form.
I don't have much experience with Ajax so I'm not sure which value to use to replace adduser-user_division_id into the select
usually I use a variable but I don't what to do with this one
The result give me empty list
error: Notice: Undefined index: division_id

The same modal used to add / edit the infos

Let me know if you need other info.


Form part

<div class="form-group">
	<label class="control-label col-md-3" for="adduser-user_division_id">
		<?php echo ASLang::get('division'); ?><span class="required">*</span>
	</label>							
	<div class="controls col-md-9">
		<?php $divisions = $db->select("SELECT * FROM `as_division`"); ?>
			<select id="adduser-user_division_id" name="adduser-user_division_id" class="form-control select2-single select2-hidden-accessible input-sm" tabindex="-1" aria-hidden="true">
				<?php foreach($divisions as $division): ?>
					<option></option>
						<?php
							echo '<option value="' . $division["division_id"] . '"' .
							(( adduser-user_division_id ==  $division["division_id"]) ? ' selected' : '') . '>' .
							 $division["division_name"] .   '</option>';
						?>
					<?php endforeach; ?>									
			</select>	
	</div>
</div>