new TomSelect("#selectTags",{
  searchInDropdown: false,
  hidePlaceholderOnSearch: true,
  hideSelected: true,
  maxOptions: 5,
  placeholder: "Start typing...",
    maxItems: 3
});

<script src="https://cdn.jsdelivr.net/npm/tom-select@2.0.3/dist/js/tom-select.complete.min.js"></script>
<link href="https://cdn.jsdelivr.net/npm/tom-select@2.0.3/dist/css/tom-select.css" rel="stylesheet"/>
<form id="myForm">
<p><input type="text" name="someText" value="testing tom select"></p>
<select id="selectTags" class="js-select form-select" name="tags[]" autocomplete="off" multiple>
  <option value="">Select a state...</option>
  <option value="AL">Alabama</option>
  <option value="AK">Alaska</option>
  <option value="AZ">Arizona</option>
  <option value="AR">Arkansas</option>
  <option value="CA" selected>California</option>
  <option value="CO">Colorado</option>
  <option value="CT">Connecticut</option>
</select>
<p><input type="submit" name="Submit" value="Submit"></p>
</form>