function ValidateContactForm()
{
    var firstname = document.ContactForm.First_Name;
    var lastname = document.ContactForm.Last_Name;
    var phone = document.ContactForm.Phone;
    var email = document.ContactForm.Email;

    if (firstname.value == "")
    {
        window.alert("Please enter your first name.");
        firstname.focus();
        return false;
    }

    if (lastname.value == "")
    {
        window.alert("Please enter your last name.");
        lastname.focus();
        return false;
    }
    
    if (phone.value == "")
    {
        window.alert("Please enter your telephone number.");
        phone.focus();
        return false;
    }

    if (email.value == "")
    {
        window.alert("Please enter a valid e-mail address.");
        email.focus();
        return false;
    }
    if (email.value.indexOf("@", 0) < 0)
    {
        window.alert("Please enter a valid e-mail address.");
        email.focus();
        return false;
    }
    if (email.value.indexOf(".", 0) < 0)
    {
        window.alert("Please enter a valid e-mail address.");
        email.focus();
        return false;
    }

    return true;
}