Javascript 从ajax更改输入中的背景 colored颜色

$('#title1').change(function(){
  var data = {"title1":$('#title1').val(),
  "title":$("#title").val()};
  $.ajax({
    type:"POST",
    url:"./atribdatt1",
    dataType:"Json",
    data:data,
    success:function(callback){
      var data_array = callback;
      artdat = data_array
      $("#vali1").html(artdat);
      document.getElementById('vali1').value = artdat;
    }
  });
});

<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>

<div class="form-group">
  <label for="title1" class="col-sm-4 control-label">NOME VISITANTE</label>
  <div class="col-sm-8">
    <select name="title1" class="form-control" id="title1">
      <option></option>
      <?php
      $sql = "SELECT * FROM raddb.Utente WHERE ativo = '1' AND codigo NOT IN ('701', '723') ORDER BY nome ASC";
      $qr = mysqli_query($conn, $sql);
      while($ln = mysqli_fetch_assoc($qr)){
      echo '<option value="'.$ln['codigo'].'">'.$ln['nome'].'</option>';
      }
      ?>
    </select>
  </div>
</div>
<div class="form-group">
  <input type="date" name="vali1" class="form-control" id="vali1" readonly="true">
</div>