             onclick="showCodeVersion('v6')"
                type="button"
                class="btn btn-secondary btn-sm"
              >
                d3 v6
              </button>
            </div>

            <!-- ========= show html code ============== -->
            <aside
              style="position: -webkit-sticky; position: sticky; top: 120px"
            >
              &larr; Edit me!
            </aside>
            <pre
              class="language-html d-none d3v4-chunk"
            >