Code:
<?php
        //If form was submitted
        if ($_POST['submitted']==1) {
            $errormsg = ""; //Initialize errors
            if ($_POST[title]){
                $title = $_POST[title]; //If title was entered
            }
            else{
                $errormsg = "Please enter title";
            }
            if ($_POST[textentry]){
                $textentry = $_POST[textentry]; //If comment was entered
            }
            else{
                if ($errormsg){ //If there is already an error, add next error
                    $errormsg = $errormsg . " & content";
                }else{
                    $errormsg = "Please enter content";
                }
            }
        }

        if ($errormsg){ //If any errors display them
            echo "<div class=\"box red\">$errormsg</div>";
        }

        //If all fields present
        if ($title && $textentry){
           //Do something
            echo "<div class=\"box green\">Form completed!</div>";
        }    
        ?>

Code:

 $greska=0
if (!trim(nadimak))
{
echo "nesto";
$greska++;
}

if (!trim(tekst))
{
echo "nesto";
$greska++;
}

if ($greska >0)
echo "nesto";
if ($greska ==1)
echo "nesto";
if ($greska>1)
echo "nesto";