function validateCommentForm(form) {
    // Name
    if (trim(form.Name.value) == "") {
        alert("You must provide your name.");
        focusField(form.Name);
        return false;
    }

    // Phone
    if (trim(form.Phone.value) == "") {
        alert("You must provide your telephone number.");
        focusField(form.Phone);
        return false;
    }

    // Email
    if (trim(form.Email.value) == "") {
        alert("You must provide your email address.");
        focusField(form.Email);
        return false;
    }

    // Country
    if (trim(form.Country.value) == "") {
        alert("You must provide your country.");
        focusField(form.Country);
        return false;
    }

    return true;
}


function focusField(field) {
    field.focus();
    field.select();
}

function trim(str) {
   return str.replace(/^\s*|\s*$/g,"");
}