Untitled

<!DOCTYPE html>
<html>
    <head>
        <title>Oppgave 1-3</title>
        <meta charset="utf-8">

        <script>
            // Register all variables
            var username, password, passwordAgain, age;

            window.onload = oppstart;

            function oppstart(){
                document.getElementById("btnRegister").onclick = visMelding;
            }

            function visMelding() {
                // Set input variables
                username = document.querySelector("input[name='Username']")
                password = document.querySelector("input[name='Password']")
                passwordAgain = document.querySelector("input[name='Passwordagain']");
                age = document.querySelector("input[name='month' 'year' 'date']");

                // If username input has no value, return error message
                if (!username.value) {
                    return alert("Du må fylle inn feltet for brukernavn")
                }

                // If the password fields have no value, return error message
                if (!password.value || !passwordAgain.value) {
                    return alert("Du må fylle inn passordfeltene")

                // If the password fields have a value, check if their given values are equal
                else if (password.value !== passwordAgain.value) {
                    return alert("Passordet må være likt i begge felt")
                }

                //If age is less than 18, return an error message
                if (age.value < 18) {
                   return alert("Du er ikke gammel nok")
               }

               alert("Du er nå registrert. Velkommen");
           }
       </script>
    </head>
    <body>
        <h1>Velkommen til registrering</h1>
        <div class="container">
            <label><b>Skriv inn brukernavn</b></label>
            <input type="text" placeholder="Skriv brukernavn" name="Username"><br/>

            <label><b>Skrive inn passord</b></label>
            <input type="password" placeholder="Skriv passord" name="Password" min="5"><br/>

            <label><b>Bekreft passord</b></label>
            <input type="password" placeholder="skriv passord på nytt" name="Passwordagain"><br/>

            <label><b>Fødselsdag</b></label>
            <input type="number" placeholder="Skriv måned" name="month">
            <input type="number" placeholder="Skriv år" name="year">
            <input type="number" placeholder="Skriv dag" name="date">
            <p type="checkbox" checked="checked"> Husk passord

            <div class="knapper">
                <button type="button" id="btnRegister">Trykk her for å registrere deg</button>
                <button type="button" id="btnCancel">Avbryt</button>
            </div>
        </div>
    </body>
</html>