<?php
$servername = "sbazy.uek.krakow.pl";
$username = "s188691";
$password = "msXLxU2r";
$dbname = "s188691";

$conn = new mysqli($servername, $username, $password, $dbname);

if ($conn->connect_error) {
   die("Connection failed: " . $conn->connect_error);
}

$tytul = $_POST["tytul"];
$tresc = $_POST["val"];

echo $tytul; //<- to dziala
echo $tresc; //<- to nie dziala

//$sql = "INSERT INTO tadek (tytul, tresc) VALUES ($tytul, $tresc)";
?>