When I try to echo most of XTHML tags inside a PHP loop which one echo's data from a MySQL it just shows text in browser. I'm running XAMPP Control Panel with Apache and MySQL for tests.
echo "<textarea readonly>";
while ($wiersz = mysql_fetch_array($sql_wynik_zapytania))
echo " ".$wiersz['NICK'].":\n";
echo $wiersz['KOMENT']."\n"."<hr />"."\n";
A textarea element can't contain anything other than plain text.
You are writing invalid HTML and the browser is trying to recover by treating the
< character as plain text instead of the start of a tag.
It looks like you aren't using the textarea to accept user input anyway (you've made it readonly). Don't use a textarea element here. You probably want to use