<?php  session_start(); ?>
<?
$link = mysql_connect("localhost", "root", "") or die ("Нет соединения с хостом");
mysql_query("SET NAMES utf8");
mysql_query('SET CHARACTER SET utf8');
mysql_query('SET COLLATION_CONNECTION="utf8_general_ci"');
mysql_select_db ("velom");
$query = mysql_query("SELECT *  FROM zapchast as z left join proizv as p on z.idpr=p.idpr where active=0") or die(mysql_error());
$idz=$_SESSION['idz'];
?>
  <script type="text/javascript" src="https://ajax.googleapis.com/ajax/libs/jquery/2.0.3/jquery.min.js"></script>
 <script src="../js/ajax.js"></script>

 <form method="post" id="ajax_form" action="" >
        <input type="text" name="name" placeholder="NAME" /><br>
        <input type="text" name="phonenumber" placeholder="YOUR PHONE" /><br>
			<?
	echo "<input name='idz' type='hidden' value='". $_SESSION['idz'] ."'><input type='text' size=60 name='vibork2' id='input' list='vibork'  />";
										echo "<datalist id='vibork'  >";
mysql_data_seek($query,0);
while ($row=mysql_fetch_array($query)) 
{
	$idv=$row[1]."|".$row[7];	
echo "<option value='".$idv."'></option>";}
echo "</datalist>";
?>	
        <input type="button" id="btn" value="Отправить" />
    <div id="result_form"><div> 
	</form>

$( document ).ready(function() {
    $("#btn").click(
		function(){
			sendAjaxForm('result_form', 'ajax_form', '../app/issklad.php');
			return false; 
		}
	);
});
 
function sendAjaxForm(result_form, ajax_form, url) {
    jQuery.ajax({
        url:     url, 
        type:     "POST", //метод отправки
        dataType: "html", //формат данных
        data: jQuery("#"+ajax_form).serialize(),  // Сеарилизуем объект
        success: function(response) { //Данные отправлены успешно
        	result = jQuery.parseJSON(response);
        	document.getElementById(result_form).innerHTML = "Количество: "+result.idu;
    	},
    	error: function(response) { // Данные не отправлены
    		document.getElementById(result_form).innerHTML = "Ошибка. Данные не отправленны.";
    	}
 	});
}
 

<?php

if (isset($_POST["vibork2"])) ) { 

$link = mysql_connect("localhost", "root", "") or die ("Нет соединения с хостом");
mysql_query("SET NAMES utf8");
mysql_query('SET CHARACTER SET utf8');
mysql_query('SET COLLATION_CONNECTION="utf8_general_ci"');
mysql_select_db ("velom");

$zappr=$_POST["vibork2"];
	$s='|';
	$k=strpos ($zappr,$s);
	$zap=substr($zappr,0,$k); 
$res=mysql_query ("SELECT IfNULL( sum( kolvo ) , 0 ) AS kolvo FROM prihod as p
left join zapchast as z on p.idzap=z.idzap where nazvzap = '$zap'");

while($row2 = mysql_fetch_array($res))
	{$idu=$row2['0'];}
	
	
	
	// Формируем массив для JSON ответа
    $result = array(
    	'idu' => $idu
    ); 

    // Переводим массив в JSON
    echo json_encode($result); 
}

?>

$( document ).ready(function() {
   $("#input").click(

		function(){
			sendAjaxForm('result_form', 'ajax_form', 'issklad.php');
			return false; 
		}
	);
});