function checkData(){
 firstname = document.emailInfo.firstname.value;
 lastname = document.emailInfo.lastname.value;
 if ((firstname=="")&&(lastname=="")){
  alert("Please enter at least your lastname")
  document.emailInfo.lastname.focus();
  return false;
 }
 phone = document.emailInfo.phone.value;
 email = document.emailInfo.email.value;
 besttime= document.emailInfo.besttime.value;
 if ((besttime=="email")&&(email=="")){
  alert("If you want to be contacted by email please enter your email address\n");
  document.emailInfo.phone.focus();
  return false;
 }
 if ((phone=="")&&(email=="")){
  alert("Please enter either your phone number or your email address\n");
  document.emailInfo.phone.focus();
  return false;
 }
 document.emailInfo.submit();
}