function validForm(form) {
var empty=false;
if (form.firstname.value.length < 1) {
  alert("Please fill in your Name");
  form.firstname.focus();
  empty=true;
}
if (form.surname.value.length < 1) {
  alert("Please fill in your Name");
  form.surname.focus();
  empty=true;
}
else if (form.email.value.length < 1) {
  alert("Please provide an e-mail address");
  form.email.focus();
  empty=true;
}
if (empty) 
  return false;
else
  return true;
}