function focusAdv(){
  if (document.formAdv.emailAdv.value == "") {
    document.formAdv.emailAdv.focus();
  }
}

// method to check form

function checkAndDelete(){

  // check name
  if (document.formAdv.emailAdv.value == "") {
    alert("Falta tu direccion email");
    document.formAdv.emailAdv.focus();
    return;
  }

  // check password
  if (document.formAdv.randomnumberAdv.value == "") {
    alert("Falta tu clave");
    document.formAdv.randomnumberAdv.focus();
    return;
  }

  document.formAdv.submit();
}

function checkAndSendData(){

  // check email address
  if (document.formDatacallAdv.emailAdv.value == "") {
    alert("Falta tu direccion email");
    document.formDatacallAdv.emailAdv.focus();
    return;
  }

  document.formDatacallAdv.submit();
}