function validate_required(field, alerttxt) {
    with (field) {
        if (value==null||value=="") {
            jQuery('#'+field.id).addClass('error');
            alert(alerttxt);
            return false;
        } else {
            jQuery('#'+field.id).removeClass('error');
            return true;
        }
    }
}

function validate_required_select(field, alerttxt) {
    with (field) {
        if (value==null||value=="") {
            jQuery('#'+field.id).addClass('error');
            alert(alerttxt);
            return false;
        } else {
            jQuery('#'+field.id).removeClass('error');
            return true;
        }
    }
}

function validate_form(thisform) {
    var invalid = "invalid!";
    var not_selected = "not selected!";

    with (thisform) {
        if (validate_required(firstname, "Firstname " + invalid) == false) {
            firstname.focus();
            return false;
        }
        if (validate_required(lastname,"Lastname "+invalid)==false) {
            lastname.focus();
            return false;
        }
        if (validate_required(company, "Company " + invalid) == false) {
            company.focus();
            return false;
        }
        if (validate_required(job, "Job function " + invalid) == false) {
            job.focus();
            return false;
        }
        if (validate_required(phone,"Phone number "+invalid)==false) {
            phone.focus();
            return false;
        }
        if (validate_required(email,"E-mail address "+invalid)==false) {
            email.focus();
            return false;
        }
        if (validate_required_select(country, "Country "+not_selected) == false) {
            country.focus();
            return false;
        }
        if (validate_required(message, "Message body " + invalid) == false) {
            message.focus();
            return false;
        }
    }
}

function validate_subscription_form(thisform) {
    var invalid = "invalid!";
    var not_selected = "not selected!";

    with (thisform) {
        if (validate_required(firstname, "Firstname " + invalid) == false) {
            firstname.focus();
            return false;
        }
        if (validate_required(lastname,"Lastname "+invalid)==false) {
            lastname.focus();
            return false;
        }
        if (validate_required(company, "Company " + invalid) == false) {
            company.focus();
            return false;
        }
        if (validate_required(email,"E-mail address "+invalid)==false) {
            email.focus();
            return false;
        }
    }
}