ajax:
var serviceid = document.getElementById('service_id').value;
var queryString = "?serviceid=" + serviceid;
ajaxRequest.open("GET", "pages/getprice.php" + queryString, true);
ajaxRequest.send(null);
while($row = mysql_fetch_array($qry_result)){
$display_string .= "<td>$row[service_price]</td>";
$display_string .= "<input type='hidden' name='servicename' id='servicename' value='$row[service_name]'>";
$display_string .= "<input type='hidden' name='servicetime' id='servicetime' value='$row[service_time]'>";
}
$display_string .= "</tr>";
$display_string .= "</table>";
echo $display_string;
$servlist .= "<option value='".$row['service_id']."'>".$row['service_name']."</option>";
} ?>
<div class="field"><span class="label">Услуга:</span><span class="box">
<select name="heading" class="logbut" onchange='ajaxFunction()' id="service_id">
<option value="">Моля Изберете</option><?=$servlist;?></select><div id='ajaxPrice' style="display:none"></div>
$event_time = htmlspecialchars($_POST["service_time"]);
$query = "INSERT INTO ..