function action(form,campo,atrib) {
    alert("Campo " + campo + " " + atrib + "!");
    form.elements[campo].style.border = "1px dotted #f00";
    form.elements[campo].focus();
    return false;
}
function valida(form) {
    var id = new Array("nome","email", "ddd","telefone");
    for (i=0; i <= id.length-1; i++) {
        if (form.elements[id[i]].value == "")
            return action(form,[id[i]],"obrigatório");
        if ([id[i]] == "email") {
            valido = /^[a-zA-Z0-9][a-zA-Z0-9\._-]+@([a-zA-Z0-9\._-]+\.)[a-zA-Z-0-9]{2}/;
            if (!valido.exec(form.elements[id[i]].value))
                return action(form,[id[i]],"inválido");
        }
    }
}