<form action='' method='post'>
Vardas: <input type='text' name='user_name'> <br />
Taškai: <input type='text' name='user_taskai'> <br />
<input type='submit' value='prideti' name='prideti'>
</form>
 
<?php
if (isset($_POST['prideti'])) {
dbquery("UPDATE ".$db_prefix."users SET users_taskai = users_taskai + ".$_POST['user_taskai']." WHERE user_name='".$_POST['user_name']."' ");
}
?>