zadania z funkcji w js

zad.1
<!DOCTYPE html>
<html lang="pl">
<head>
<meta charset="utf-8" />
<script type="text/javascript">
let a = parseInt(prompt("Podaj liczbe"));

function wartosc_bezwzgledna(a)
{
    if(a>=0)
    document.write(a);
    else
    document.write(a*-1);
}

wartosc_bezwzgledna(a);

</script>
</head>
<body>
</body>
</html>

zad.2
<!DOCTYPE html>
<html lang="pl">
<head>
<meta charset="utf-8" />
<script type="text/javascript">
let a = parseInt(prompt("Podaj liczbe"));

function czy_parzysta(a)
{
    if(a%2==0)
    document.write(true);
    else
    document.write(false);
}

czy_parzysta(a);

</script>
</head>
<body>
</body>
</html>

zad.3
<!DOCTYPE html>
<html lang="pl">
<head>
<meta charset="utf-8" />
<script type="text/javascript">
let a = prompt("Podaj znak");
let b = parseInt(prompt("Podaj dlugosc"));

function szlaczek(a,b)
{
    for(let i=1; i<=b; i++)
    {
        document.write(a);
    }
}

szlaczek(a,b);

</script>
</head>
<body>
</body>
</html>

zad.5
<!DOCTYPE html>
<html lang="pl">
<head>
<meta charset="utf-8" />
<script type="text/javascript">

let a = parseInt(prompt("Podaj bok trojkata"));
let b = parseInt(prompt("Podaj bok trojkata"));
let c = parseInt(prompt("Podaj bok trojkata"));

function obwod_trojkata(a,b,c)
{
    document.write(a+b+c);
}

obwod_trojkata(a,b,c);

</script>
</head>
<body>
</body>
</html>