echo 'Hallo world!';

$s = 'hallo world!';
$s = strtoupper( s{0} ) . substr($s, 1, strlen($s) - 1 );
print_r($r);

abstract class outPut
{

  static public function outContent($content){
     echo $content;
  }    

}
    
class outPutHalloWorld extends outPut
{

  public function outPut(){

    $this->outContent('Hallo wordl!');

  }

}

$out = new outPut();
$out->outPut();

alert(Hallo wordl!);