如何将新的Div添加到特定元素

<script type="text/javascript">
                         $(document).ready(function(){
                             $('a#extra').click(function(event){
                                if($(this).attr('class') == 'extra'){
                                    event.preventDefault();
                                    $(this).append('<div style="float:left;color:red;margin-left:10px;">Please Login/Register to view Details</div>').slideToggle(1000);

                                }
                             });
                         });
                     </script>

我有这个jquery用于根据锚属性中的类添加div.

I have this jquery for adding div according to class in anchor attribute.

<a href="" class="extra_1" id="extra"></a>
<a href="" class="extra_2"  id="extra"></a>
<a href="" class="extra_3"  id="extra"></a>

我可以像上面显示的代码一样检查类，但是如何检查extra_1，extra_2，extra_3，例如是否单击了具有extra_1类的元素，然后将其添加到该元素中

i can check for class like the code shown above, but how can i check for extra_1, extra_2, extra_3, like if element with extra_1 class is clicked then add to that element