รบกวนสอบถามเกี่ยวกับการ ส่งค่า id ไป form ของ modal-dialog

<form method="POST" action="   ">
<input type="hidden" id="hdnID" name="hdnID" value="">
<div class="modal fade" id="addBookDialog" tabindex="-1" role="dialog" aria-labelledby="myModalLabel" aria-hidden="true">
    <div class="modal-dialog modal-lg">
        <div class="panel panel-primary">
            <div class="panel-heading">
                <button type="button" class="close" data-dismiss="modal" aria-hidden="true" OnClick="document.form1.hdnID.value='xyz';">&times;</button>
                <h3 class="modal-title" id="myModalLabel">test</h3>
            </div>
            <div class="panel-body">
     
            </div>
            <div class="panel-footer">                
               
            </div>
        </div>
    </div>
</div>
</form>