I have a dynamic number of select elements. When the form is submitted, I want to check if any of them have not been selected yet ie the `value == ""`, if so throw an error, any ideas how I do this please in Jquery? Thanks!

```
<div class="container-seller-commission">
  <div class="row-seller-commission">
    <select name="seller" id="seller" class="select-seller valid">
      <option value=""></option>
      <option value="4" selected="selected">Agent</option>
      <option value="2">Crisalix Global</option>
      <option value="1">Owner</option>
      <option value="3">Support</option>
    </select>
  </div>
</div>
<div class="row-seller-commission">
  <select name="seller" id="seller" class="select-seller valid">
    <option value=""></option>
    <option value="4" disabled="disabled">Agent</option>
    <option value="2" selected="selected">Crisalix Global</option>
    <option value="1">Owner</option>
    <option value="3">Support</option>
  </select>
</div>
<div class="row-seller-commission">
  <select name="seller" id="seller" class="select-seller valid">
    <option value=""></option>
    <option value="4" disabled="disabled">Agent</option>
    <option value="2">Crisalix Global</option>
    <option value="1" selected="selected">Owner</option>
    <option value="3" disabled="disabled">Support</option>
  </select>
</div>

```