header-search.html

              <div class="dropdown">
                <button class="btn btn-default dropdown-toggle" type="button" data-toggle="dropdown" aria-haspopup="true" aria-expanded="true" aria-label="Toggle Search">
                  <i class="glyphicon glyphicon-search" aria-hidden="true"></i>
                </button>
                <ul class="dropdown-menu dropdown-menu-right">
                  <li>
                    <form role="search" action="https://library.caltech.edu/srch.php">
                      <div class="input-group">
                        <input type="search" name="q" class="form-control" placeholder="Search Our Website" aria-label="Our Website">
                        <span class="input-group-btn">
                          <button class="btn btn-default" type="submit">
                            Search
                          </button>
                        </span>
                      </div>
                    </form>
                  </li>
                </ul>
              </div>