/**
 * Returns _true_ if validation fails; _false_ otherwise.
 */
function validateText(id, message) {
    var element = document.getElementById(id);
    if (!element) {
        alert("element not found: \"" + id + "\"");
        return true;
    }
    element.value = StringUtil_trim(element.value);
    if (!element.value) {
        element.focus();
        alert(message);
        return true;
    }
    return false;
}

/**
 * Returns _true_ if validation fails; _false_ otherwise.
 */
function validateEmail(id, optional, message) {
    var element = document.getElementById(id);
    if (!element) {
        alert("element not found: \"" + id + "\"");
        return true;
    }
    element.value = StringUtil_trim(element.value);
    if (!EmailValidation_validate(element.value, optional, false)) {
        element.focus();
        alert(message);
        return true;
    }
    return false;
}