<input class="ultimo-valor" onKeyUp="ultimoValor(this)" type="text"
value="<?php echo $ultimo_valor; ?>"/>

<input class="ultimo-valor" onKeyUp="ultimoValor(this)" type="text"
value="<?php echo $ultimo_valor; ?>"/>

<script>
$(document).ready(
   function ultimoValor(e) {
      $('.ultimo-valor').on("change paste keyup", function() {
       alert($(this).val());
      });
});
</script>