call ajax value from modal form indo the same modal window
===

I have this simple cod:

jQuery:

     function suggestPtype() {
    $.ajax({type:'POST', url: 'include/suggest_ptype_categ.php', data:$('#ptype_form').serialize(), success: function(response) {
        $('#ptype_form').find('.ptype_thanks').html(response);
    }});
    return false;
}

HTML:

    <div id="ptype_box" class="ptype_popup">
					<a href="#" class="close"><img src="<?php echo $_SERVER["SITE_HTMLROOT"]?>/images/close.png" class="btn_close" title="Close Window" alt="Close" /></a>
						<form method="post" id="ptype_form" onsubmit="return suggestPtype();">
								<span>Product Type</span><input class="required" name="suggest_ptype" value="" type="text" autocomplete="off" placeholder="Product Type"><br />
								<?php 
									$namecat=$langid."_name";
									$result1 = mysql_query ( "SELECT categories.id, categories.$namecat FROM categories LEFT JOIN ptype_new ON ( ptype_new.catid LIKE concat( '%::', categories.id, '::%' ) ) WHERE ptype_new.id =12" ) or die(mysql_error());
									while($row2 = mysql_fetch_array($result1)){
										echo '<input type="checkbox" name="suggest_cat[]" value="'.$row2[0].'"><span id="label" style="padding-left:10px;color:#ffffff; font:13px Arial,Helvetica,sans-serif;">'.$row2[1].'</span><br/>';} ?>
								<button class="submit button" type="submit" id="doSuggestPtype" name="doSuggestPtype">Save</button>
								<div class="ptype_thanks"></div>
						</form>
				</div>

php:

    
    <?php
if(isset($_POST['doSuggestPtype'])) {
	$suggest_ptype = $_POST['suggest_ptype'];
   
   echo " Your Name Is:".$suggest_ptype; ?>



class="ptype_popup" is a modal window.
I want to call values from the form in the same form (popup) with ajax calling but I don't manage.
where do I wrong

Thanks
Cosmin