function checkInput(formular) {
    var message = "";
    var error   = false;

    switch(formular) {
        case "CancellationForm":
            if(document.forms[formular].confirmationNumber.value.length != '') {
                error   = true;
                message = "";
            } else {
                message = document.getElementById('rate_form_input_err_email_critic').value;
            }
            break;
        case "CancellationLogin":
            if(document.forms[formular].itineraryId.value.length != '' && document.forms[formular].email.value.length != '') {
                error   = true;
                message = "";
            } else {
                message = document.getElementById('rate_form_input_err_email_critic').value;
            }
            break;
        case "FormSearch":
            if(document.forms[formular].destination.value.length != 0) {
                error   = true;
                message = "";
            } else {
                message = document.getElementById('formsearch_input_err_dest').value;
            }

            if((document.forms[formular].ArrivalDay.value.length == 0 &&
                document.forms[formular].DepartureDay.value.length != 0) ||
               (document.forms[formular].ArrivalDay.value.length != 0 &&
                document.forms[formular].DepartureDay.value.length == 0)) {

                error   = false;
                message = document.getElementById('formsearch_input_err_arr_and_dep').value;

            }
            break;
        case "FormSearchLandmarkForm":
            if((document.getElementById('ArrivalDayLandmark').value.length == 0 &&
                document.getElementById('DepartureDayLandmark').value.length != 0) ||
               (document.getElementById('ArrivalDayLandmark').value.length != 0 &&
                document.getElementById('DepartureDayLandmark').value.length == 0)) {

                error   = false;
                message = document.getElementById('formsearch_input_err_arr_and_dep').value;

            }
            break;

        case "HotelFormSearch":
            if((document.forms[formular].ArrivalDay.value.length == 0 &&
                document.forms[formular].DepartureDay.value.length == 0) ||
               (document.forms[formular].ArrivalDay.value.length == 0 &&
                document.forms[formular].DepartureDay.value.length != 0) ||
               (document.forms[formular].ArrivalDay.value.length != 0 &&
                document.forms[formular].DepartureDay.value.length == 0)) {

                error   = false;
                message = document.getElementById('hotelformsearch_form_input_err_arr_and_dep').value;

            } else {
                error = true;
            }
            break;

        case "CityFormSearch":
            if((document.forms[formular].ArrivalDay.value.length == 0 &&
                document.forms[formular].DepartureDay.value.length != 0) ||
               (document.forms[formular].ArrivalDay.value.length != 0 &&
                document.forms[formular].DepartureDay.value.length == 0)) {

                error   = false;
                message = document.getElementById('cityformsearch_form_input_err_arr_and_dep').value;

            } else {

                if(document.forms[formular].hotelname.value.length != 0 ||
                   (document.forms[formular].ArrivalDay.value.length != 0 &&
                    document.forms[formular].DepartureDay.value.length != 0)) {
                    error = true;
                } else {
                    error   = false;
                    message = document.getElementById('cityformsearch_form_input_err_arr_and_dep_alternative').value;
                }

            }
            break;

        case "RateForm":
            if(document.forms[formular].agb.checked == true) {
                if(document.forms[formular].email.value.length == 0 ||
                   document.forms[formular].hotel_name.value.length == 0 ||
                   document.forms[formular].critic.value.length == 0) {
                    errror  = false;
                    message = document.getElementById('rate_form_input_err_email_critic').value;
                } else {
                    error = true;
                }
            } else {
                message = document.getElementById('rate_form_input_err_agb_critic').value;
                error = false;
            }
            break;

        default:
            if(document.forms[formular].name.value.length == 0 ||
               document.forms[formular].email.value.length == 0 ||
               document.forms[formular].subject.value.length == 0 ||
               document.forms[formular].message.value.length == 0) {
                error   = false;
                message = document.getElementById('contact_form_message').value;
            } else {
                error = true;
            }


    }
    if(message.length > 0) {
        alert(message);
    } else {
        if(formular != "RateForm" && formular != "CancellationLogin" && formular != "CancellationForm") {
            showLoadingPage(formular);
        }
    }
    return error;

}