title: Showing/hiding checkbox based on another checkbox selection
body: <p>Looking to have it so that when the first checkbox is selected (<code>geographic_checkbox</code>), a further 2 checkboxes are displayed (<code>regions,cities &amp;towns_checkbox</code> and <code>ringfencing_checkbox</code>), but for some reason my code is not working.</p>
  
  <p><div class="snippet" data-lang="js" data-hide="false" data-console="true" data-babel="false">
  <div class="snippet-code">
  <pre class="snippet-code-js lang-js prettyprint-override"><code>$('#geographic_checkbox').on('click', function() {
    if (this.checked) {
      $('#geographic_suboptions').removeClass('hidden');
    } else {
      $('#geographic_suboptions').addClass('hidden');
    }
  });</code></pre>
  <pre class="snippet-code-css lang-css prettyprint-override"><code>.hidden {
    display: none;
  }</code></pre>
  <pre class="snippet-code-html lang-html prettyprint-override"><code>&lt;script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"&gt;&lt;/script&gt;
  &lt;div class="targeting"&gt;
    &lt;h1&gt;Targeting&lt;/h1&gt;
    &lt;ul&gt;
      &lt;li&gt;
        &lt;input type="checkbox" name="geographic" value="0.00" id="geographic_checkbox" onclick="GeographicFunction()"&gt;Geographic&lt;br&gt;
        &lt;p id="geographic_text" style="display:none"&gt;+£0.08 CPC&lt;/p&gt;
        &lt;div id="geographic_suboptions" class="hidden"&gt;
          &lt;ul&gt;
            &lt;li&gt;&lt;input type="checkbox" name="regions,cities&amp;towns" value="0.08" id="regions,cities&amp;towns_checkbox" onclick="RegionsFunction()"&gt;Regions, Cities &amp; Towns&lt;br&gt;&lt;/li&gt;
            &lt;p id="regions,cities&amp;towns_text" style="display:none"&gt;+£0.08 CPC&lt;/p&gt;
            &lt;li&gt;&lt;input type="checkbox" name="ringfencing" value="0.09" id="ringfencing_checkbox" onclick="RingfencingFunction()"&gt;Ring-Fencing&lt;br&gt;&lt;/li&gt;
            &lt;p id="ringfencing_text" style="display:none"&gt;+£0.08 CPC&lt;/p&gt;
          &lt;/ul&gt;
        &lt;/div&gt;
      &lt;/li&gt;
    &lt;/ul&gt;
  &lt;/div&gt;</code></pre>
  </div>
  </div>
  </p>