function form_step3(id) {

	id = document.getElementById(id);

    if (id.so7.value == "4499") {
        id.v7.className = "A_required A_digit";
        id.v8.className = "A_email";
    }
    if (id.so7.value == "4500") {
        id.v8.className = "A_required A_email";
        id.v7.className = "A_digit";
    }

}

function contact_form_prefered(id) {

	id = document.getElementById(id);

    if (id.pref_kontakt.value == "4499") {
        id.tel.className = "A_required A_digit";
        id.email.className = "A_email";
    }
    if (id.pref_kontakt.value == "4500") {
        id.email.className = "A_required A_email";
        id.tel.className = "A_digit";
    }

}

function formShow(id) {
	id = document.getElementById(id);
   	id.style.display = 'block';
}