jQuery after bug demonstration

HTML

<div id="filter-wrapper" class="group">


<form name="filter" action="https://compare.zen4all-dev.nl/index.php?main_page=index" method="get"><label class="inputLabel">Filter Results by:</label><input type="hidden" name="main_page" value="index"><input type="hidden" name="cPath" value="1_4"><input type="hidden" name="sort" value="20a"><select id="select-alpha_filter_id" name="alpha_filter_id" onchange="this.form.submit()">
  <option value="0">Items starting with ...</option>
  <option value="65">A</option>
  <option value="66">B</option>
  <option value="67">C</option>
  <option value="68">D</option>
  <option value="69">E</option>
  <option value="70">F</option>
  <option value="71">G</option>
  <option value="72">H</option>
  <option value="73">I</option>
  <option value="74">J</option>
  <option value="75">K</option>
  <option value="76">L</option>
  <option value="77">M</option>
  <option value="78">N</option>
  <option value="79">O</option>
  <option value="80">P</option>
  <option value="81">Q</option>
  <option value="82">R</option>
  <option value="83">S</option>
  <option value="84">T</option>
  <option value="85">U</option>
  <option value="86">V</option>
  <option value="87">W</option>
  <option value="88">X</option>
  <option value="89">Y</option>
  <option value="90">Z</option>
  <option value="48">0</option>
  <option value="49">1</option>
  <option value="50">2</option>
  <option value="51">3</option>
  <option value="52">4</option>
  <option value="53">5</option>
  <option value="54">6</option>
  <option value="55">7</option>
  <option value="56">8</option>
  <option value="57">9</option>
</select>
</form>

</div>

CSS

body {
    font-family: Helvetica, Arial, sans-serif;
}

h1 {
    margin-top: 20px;
    font-size: 20px;
    font-weight: bold;
}

JavaScript

var compareResultDiv;
  compareResultDiv = '';
  compareResultDiv += '<div id="compareResult" class="group">' + "\n";
  compareResultDiv += '  <div class="back compareText"><strong>HALLO</div>' + "\n";
  compareResultDiv += '    <div id="compareProducts">' + "\n";
  
    compareResultDiv += 'TEST    </div>' + "\n";
  compareResultDiv += '  </div>' + "\n";
  compareResultDiv += '</div>' + "\n";
  $('#filter-wrapper').after(compareResultDiv);