I have a page with a form with data filled by ajax post; on form page fields values are loaded correctly but I cannot get loaded value from a function inside the page; here is an example:

```
<input type="text" id="mela">
<div style="border:1px solid black; display:none" id="vv">aaa</div>

<script>
  alert($("#mela").val());
  if ($("#mela").val()) {
    $("#vv").show();
  }
</script>

```

The question is: how can I get "mela" value loaded?