JavaScript doesn't work in my frames?!

Answer 1

Remove the semicolon ";" after login()

JavaScript is seeing that as the end of statement, and not taking into account the function body. It's still valid JavaScript, but it's not a function definition.

function logIn() {

 var username = prompt("Skriv venligst dit brugernavn:" , "");

var password = prompt("Skriv venligst dit password:" , "");
// ... etc...