อยากทราบว่า ใน form ถ้าเราไม่ได้กรอกข้อมูล อยากจะให้มีการแจ้งเตือนในหน้าครับ

<?php
if (!function_exists("GetSQLValueString")) {
function GetSQLValueString($theValue, $theType, $theDefinedValue = "", $theNotDefinedValue = "") 
{
  if (PHP_VERSION < 6) {
    $theValue = get_magic_quotes_gpc() ? stripslashes($theValue) : $theValue;
  }

  $theValue = function_exists("mysql_real_escape_string") ? mysql_real_escape_string($theValue) : mysql_escape_string($theValue);

  switch ($theType) {
    case "text":
      $theValue = ($theValue != "") ? "'" . $theValue . "'" : "NULL";
      break;    
    case "long":
    case "int":
      $theValue = ($theValue != "") ? intval($theValue) : "NULL";
      break;
    case "double":
      $theValue = ($theValue != "") ? doubleval($theValue) : "NULL";
      break;
    case "date":
      $theValue = ($theValue != "") ? "'" . $theValue . "'" : "NULL";
      break;
    case "defined":
      $theValue = ($theValue != "") ? $theDefinedValue : $theNotDefinedValue;
      break;
  }
  return $theValue;
}
}

$editFormAction = $_SERVER['PHP_SELF'];
if (isset($_SERVER['QUERY_STRING'])) {
  $editFormAction .= "?" . htmlentities($_SERVER['QUERY_STRING']);
}

if ((isset($_POST["MM_insert"])) && ($_POST["MM_insert"] == "addadmin")) {
  $insertSQL = sprintf("INSERT INTO adminsystem (uname, upass) VALUES (%s, %s)",
                       GetSQLValueString($_POST['uname'], "text"),
                       GetSQLValueString($_POST['upass'], "text"));
  mysql_select_db($database_config, $config);
  $Result1 = mysql_query($insertSQL, $config) or die(mysql_error());

  $insertGoTo = "editadmin.php";
  if (isset($_SERVER['QUERY_STRING'])) {
    $insertGoTo .= (strpos($insertGoTo, '?')) ? "&" : "?";
    $insertGoTo .= $_SERVER['QUERY_STRING'];
  }
  header(sprintf("Location: %s", $insertGoTo));
}

$maxRows_RecordAdmin = 10;
$pageNum_RecordAdmin = 0;
if (isset($_GET['pageNum_RecordAdmin'])) {
  $pageNum_RecordAdmin = $_GET['pageNum_RecordAdmin'];
}
$startRow_RecordAdmin = $pageNum_RecordAdmin * $maxRows_RecordAdmin;

mysql_select_db($database_config, $config);
$query_RecordAdmin = "SELECT * FROM adminsystem";
$query_limit_RecordAdmin = sprintf("%s LIMIT %d, %d", $query_RecordAdmin, $startRow_RecordAdmin, $maxRows_RecordAdmin);
$RecordAdmin = mysql_query($query_limit_RecordAdmin, $config) or die(mysql_error());
$row_RecordAdmin = mysql_fetch_assoc($RecordAdmin);

if (isset($_GET['totalRows_RecordAdmin'])) {
  $totalRows_RecordAdmin = $_GET['totalRows_RecordAdmin'];
} else {
  $all_RecordAdmin = mysql_query($query_RecordAdmin);
  $totalRows_RecordAdmin = mysql_num_rows($all_RecordAdmin);
}
$totalPages_RecordAdmin = ceil($totalRows_RecordAdmin/$maxRows_RecordAdmin)-1;
?>

<div class="col-xl-4">
                        <form action="<?php echo $editFormAction; ?>" method="post" name="addadmin" id="addadmin">
                         <div class="exfonts">Username:</div>
                        <input type="text" class="form-control" name="uname" id="uname" value="" size="32" />
                        <div class="exfonts">Password:</div>
                        <input type="password" class="form-control" name="upass" value="" size="32" />
                      <p>&nbsp;</p>
                        <button type="submit" class="btn btn-success">Save changes</button>
                       <input type="hidden" name="MM_insert" value="addadmin" />
                        </form>                   
   </div>