<div class="btn-group">
    <button type="button" class="btn btn-primary dropdown-toggle" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">
                        在線觀看
                        <span class="caret"></span>
                        <span class="sr-only">Toggle Dropdown</span>                  
    </button>
                    <ul class="dropdown-menu">
                        {% for i in other_info.videos %}
                        <li>
                            <a href="{{i.sample_link}}" target="_blank">
                                <span>{{i.source.name}} - </span>
                                <span>
                                    {% if i.need_pay %}
                                    收費
                                    {%else%}
                                    <span style="color:#4da8ec">免費!</span>
                                    {%endif%}
                                </span>
                            </a>
                        </li>
                        {% endfor %}
                        <li role="separator" class="divider"></li>
                        <li><a  target="_blank">豆瓣網(wǎng)中搜索</a></li>
                    </ul>
                </div>