<form method="post" action="../controller/SendChatMessage.class.php?act=open_chat&id_unique_talk=<?=$get_id_unique_talk?>&to_id=<?=$get_id_para?>" id="send_message_chat" ajax="true">
  <div class="col-sm-10">
     <div class="message-area">
        <textarea placeholder="Message" rows="10" name="message" id="txt_message"></textarea>
     </div>
  </div>

<script type="text/javascript">
$(document).ready(function(e) {

  $("form[ajax=true]").submit(function(e) {

      e.preventDefault();

      var form_data = $(this).serialize();
      var form_url = $(this).attr("action");
      var form_method = $(this).attr("method").toUpperCase();

      $("#loading").show();

      $.ajax({
          url: form_url,
          type: form_method,
          data: form_data,
          cache: false,
          success: function(returnhtml){
              $("#result").html(returnhtml);
              $("#loading").hide();
              document.getElementById('txt_message').value='';
          }
      });

  });