function show_form_error(elem, text){

    id_ext = elem.id;

    if(document.getElementById('form_error_' + id_ext)){
        document.getElementById('form_error_' + id_ext).innerHTML = text;
        //new Effect.Highlight('form_error_' + id_ext);
        $('#form_error_' + id_ext).show();
    } else {
        var div = document.createElement('div');
        div.className = 'telluser_error';
        div.id = 'form_error_' + id_ext;
        div.innerHTML = text;

        div.style.display = 'none';

        elem.className = 'error';
        elem.parentNode.appendChild(div);

        //new Effect.BlindDown('form_error_' + id_ext, {duration: 0.5});
        $('#form_error_' + id_ext).show('normal');
    }
 }

 function hide_form_error(elem){

    id_ext = elem.id;

    elem.className = '';
    if(document.getElementById('form_error_' + id_ext)){
        //new Effect.BlindUp('form_error_' + id_ext, {duration: 0.5});
        $('#form_error_' + id_ext).hide('normal');
    }
 }

function checkContact(form){

    var error = false;
    var hide_error = new Array();

	if(form.nachname.value == ''){
        show_form_error(form.nachname, 'Bitte geben Sie einen Nachnamen an.');
        error = true;
    } else {
        hide_error[hide_error.length] = form.nachname;
    }

    if(form.vorname.value == ''){
        show_form_error(form.vorname, 'Bitte geben Sie auch einen Vornamen an.');
        error = true;
    } else {
        hide_error[hide_error.length] = form.vorname;
    }

    var RegExpr = /^[\w\d-_]+(\.[_\w\d-]+)*@[\w\d-]+(\.[_\w\d-]+)*\.([\w]{2,5})$/i;
    if((!RegExpr.exec(form.email.value) || form.email.value == '') || (!RegExpr.exec(form.email2.value) || form.email2.value == '') ){
        show_form_error(form.email, 'Bitte geben Sie eine gültige E-Mail-Adresse an.');
        error = true;
    }else{
		hide_error[hide_error.length] = form.email;
    }

    if(form.nachricht.value == ''){
        show_form_error(form.nachricht, 'Bitte teilen Sie uns doch in ein paar Sätzen den Grund Ihres Kontaktes mit.');
        error = true;
    } else {
        hide_error[hide_error.length] = form.nachricht;
    }

    if(error){
        var i;
        for(i = 0; i < hide_error.length; i++){
            hide_form_error(hide_error[i]);
        }
    }

    return !error;
}