鼠标滑过,展示下拉菜单的一个特效,具体代码如下: html文件代码: div class="user" div class="dropdown" a class="dropdown-toggle" data-toggle="dropdown" style="cursor: pointer;" {% if login_user_pic is not None %} img src="{{static_url("upload/img/" + login_user_pic)}}" class="img-circ