valore di default combobox

[Annuitcoeptis]

Buongiorno, con uno userscript da questa pagina, nel combobox "N. inventario da" sto cercando di impostare come valore di default "CIN".

a2023-06-22 11 08 55.png


Questo è il relativo codice HTML:

<tr id="serieinvda">
  <td width="20%" colspan="4"><label>N. inventario&nbsp;da</label></td>
  <td width="80%" colspan="16">
    <select id="idserieDa" name="serieDa" style="min-width: 0px; display: none;">
<option value="   ">   </option>
<option value="CDM">CDM</option>
<option value="CIN">CIN</option>
<option value="PER">PER</option>
</select><div class="chosen-container chosen-container-single chosen-container-single-nosearch" style="width: 84px;" title="" id="idserieDa_chosen"><a class="chosen-single chosen-single-with-deselect" tabindex="-1"><span>   </span><abbr class="search-choice-close"></abbr><div><b></b></div></a><div class="chosen-drop"><div class="chosen-search"><input type="text" autocomplete="off" readonly=""></div><ul class="chosen-results"></ul></div></div>
<input type="text" name="invDa" value="" maxlength="9" size="11">
  </td>
</tr>




<select id="idserieDa" name="serieDa" style="min-width: 0px; display: none;">
<option value="   ">   </option>
<option value="CDM">CDM</option>
<option value="CIN">CIN</option>
<option value="PER">PER</option>
</select>

Grazie!


P.S. Usercript provato con insuccesso:

window.addEventListener('load', function() {
  var combobox = document.getElementById('idserieDa');
  
  combobox.value = 'CIN';
});