Untitled

<html>
<body>
<p id="demo"></p>
<p id="demo3"></p>
<p id="demo4"></p>
<script>
var a = new Date(2019,10,15);
document.getElementById("demo").innerHTML = a;
var b =  a.getDay();
switch(b)
    {
             case 1:
        document.getElementById("demo3").innerHTML = "Poniedzialek";
        break;
             case 2:
        document.getElementById("demo3").innerHTML = "Wtorek";
        break;
             case 3:
        document.getElementById("demo3").innerHTML = "Sroda";
        break;
             case 4:
        document.getElementById("demo3").innerHTML = "Czwartek";
        break;
             case 5:
        document.getElementById("demo3").innerHTML = "Piatek";
        break;
             case 6:
        document.getElementById("demo3").innerHTML = "Sobota";
        break;
             case 7:
        document.getElementById("demo3").innerHTML = "Niedziela";
        break;

    };

var c = a.getMonth();
var tablica = ['Stycznen','Luty','Marzec','Kwiecien','Maj','Czerwiec','Lipiec','Sierpien','Wrzesien','Pazdziernik','Listopad','Grudzien'];
document.getElementById("demo4").innerHTML = tablica[c];
</script>
</body>
</html>