function have_value (v) {

    if( v == null || v.length == 0 || /^\s+$/.test(v) ) {
        return false;
    }
    return true;
}

function validar_correo(direccion) {
    return (/\w+([-+.']\w+)*@\w+([-.]\w+)*\.\w+([-.]*\w+)/.test(direccion));
}

function contact_control(form) {

    var name = form.dname.value;
    var email = form.demail.value;
    var phone = form.dphone.value;
    var bir = form.dbirthday.value;
	var rta = true;
    if( !have_value(name) ) {
        form.dname.value="Enter your name";
		form.dname.style.border= "1px solid #ff0000";
        form.dname.focus();
		rta = false;
    }
    if( !have_value(email) ) {
        form.demail.value="Enter your e-mail";
		form.demail.style.border= "1px solid #ff0000";
        form.demail.focus();
		rta = false;
    }
    if( !have_value(phone) ) {
        form.dphone.value="Enter your phone";
		form.dphone.style.border= "1px solid #ff0000";
        form.dphone.focus();
		rta = false;
    }
    if( !have_value(bir) ) {
        form.dbirthday.value="Enter your birthday";
		form.dbirthday.style.border= "1px solid #ff0000";
        form.dbirthday.focus();
		rta = false;
    }
	
    if(!validar_correo(email)) {
        form.demail.value="Enter a valid e-mail";
		form.demail.style.border= "1px solid #ff0000";
        form.demail.focus();
		rta = false;
    }
    return rta;
}