Select new option and array compare

by emfuentes27

HTML

<select class="topicSelect" multiple>
  <optgroup label="Crops">
    <option value="">Select one</option>
    <option value="Apiculture">Apiculture</option>
    <option value="Apples">Apples</option>
    <option value="Aquaculture">Aquaculture</option>
    <option value="Blueberries">Blueberries</option>
  </optgroup>
  <optgroup label="Add Option" class="youOwn">
    <option value="own">Add Your Option</option>
  </optgroup>
</select>

JavaScript

var topicArray = ['Apples', 'Tomatoes'];

populateExistingDropDowns('topicSelect', topicArray);


function populateExistingDropDowns(dd, array) {
  var select = document.getElementsByClassName(dd);
  var opt = document.createElement('option');
  for (var d = 0; d < array.length; d++) {
    for (var q = 0; q < select[0].length; q++) {
      if (select[0].options[q].text !== array[d]) {
        opt.value = array[d];
        opt.text = array[d];
        select[0].children[1].appendChild(opt);
        opt.selected = true;
      } else {
        select[0].options[q].selected = true;
      }
    }
  }
}