var correct = true

function checkData()
{
    correct = true;
    var EmailCorrect = false;
    var EMLength = document.Home_e_mail1.Eingabefeld1.value.length;

    if (document.Home_e_mail1.Eingabefeld1.value == "")
    {
        correct = false;
        alert("Bitte geben Sie Ihre E-Mail-Adresse ein.")
    }
    if (document.Home_e_mail1.Eingabefeld1.value == "Meine@e-mail.de")
    {
        correct = false;
        alert("Bitte geben Sie Ihre E-Mail-Adresse ein.")
    }

    if (correct == true)
    {

        for (var i = 0; i <= document.Home_e_mail1.Eingabefeld1.value.length; i++)
        {
            if (document.Home_e_mail1.Eingabefeld1.value.charAt(i) == "@")
            {
                EmailCorrect = true;
            }
        }

        if (EmailCorrect==false)
        {
            correct = false;
            alert("Die eingegebene E-Mail-Adresse ist nicht gültig. Kein @-Zeichen vorhanden.")
        }
    }

    if (EmailCorrect == true)
    {
        for (var i = 0; i <= document.Home_e_mail1.Eingabefeld1.value.length; i++)
        {
            if (document.Home_e_mail1.Eingabefeld1.value.charAt(i) == " ")
            {
                EmailCorrect = false;
            }
        }
        if (EmailCorrect==false)
        {
            correct = false;
            alert("Die eingegebene E-Mail-Adresse ist nicht gültig. Leerzeichen in der E-Mail-Adresse sind nicht erlaubt.")
        }

    }

    if (EmailCorrect == true)
    {
        if (document.Home_e_mail1.Eingabefeld1.value.substr(0,4) == "www.")
        {
            correct = false;
            EmailCorrect = false;
            alert("Die E-Mail-Adresse ist nicht gültig.")
        }
    }

    if (EmailCorrect == true)
    {
        if (    document.Home_e_mail1.Eingabefeld1.value.substr(EMLength - 3, EMLength) == ".de"
                ||
                document.Home_e_mail1.Eingabefeld1.value.substr(EMLength - 3, EMLength) == ".ch"
                ||
                document.Home_e_mail1.Eingabefeld1.value.substr(EMLength - 3, EMLength) == ".at"
                ||
                document.Home_e_mail1.Eingabefeld1.value.substr(EMLength - 3, EMLength) == ".it"
                ||
                document.Home_e_mail1.Eingabefeld1.value.substr(EMLength - 3, EMLength) == ".nl"
                ||
                document.Home_e_mail1.Eingabefeld1.value.substr(EMLength - 3, EMLength) == ".fr"
                ||
                document.Home_e_mail1.Eingabefeld1.value.substr(EMLength - 4, EMLength) == ".com"
                ||
                document.Home_e_mail1.Eingabefeld1.value.substr(EMLength - 4, EMLength) == ".net"
                ||
                document.Home_e_mail1.Eingabefeld1.value.substr(EMLength - 4, EMLength) == ".org"
                ||
                document.Home_e_mail1.Eingabefeld1.value.substr(EMLength - 4, EMLength) == ".edu"
                ||
                document.Home_e_mail1.Eingabefeld1.value.substr(EMLength - 3, EMLength) == ".dk"
            )
        {
            correct = true;
            EmailCorrect = true;
        }
        else
        {
            correct = false;
            EmailCorrect = false;
            alert("Diese E-Mail-Adresse wird nicht angenommen.")
        }
    }

    return correct

}