Jquery .Click event only triggering first button in the loop

Jquery .click event only triggers the first button! I loop through data and add buttons to each on my html page and would like each button to trigger a dialog box when clicked.. But only the first one works! the rest seem to have no click event.

$(document).ready(function () {

$("#btn_comment").click(function () {
 
     $("#createComment").dialog(
                             {
                                 modal: true,
                                 height: 300,
                                 width: 500,
                                 buttons: {
                                     "Create a Comment": function () {
                                     var post_id = $(this).parent().attr("id");
                                     var desc_to_create = $("#txtComment").val();
                                     $.post("CreateComment", { "id": "", "username": "x", "post_id": post_id, "description": desc_to_create, "created": "" }, function (t) {
 
                                             alert("Thank you! Your comment has been updated!!");
                                             location.reload();
 
                                         })
 
 
                                     },
                                     "Cancel": function () {
                                         $(this).dialog("close");
                                     }
                                 }
                             }
                             );
 })
 

})

    <tr id='<%= Html.Encode(item.id) %>'>
         <td>
 
             <%: Html.ActionLink("Details", "Details", New With {.id = item.id})%> |
               <a href="javascript://" class="delete_btn">Delete</a>
 
         </td>
       <%--  <td>
             <%: item.id %>
         </td>
         <td>
             <%: item.username %>
         </td>
         <td>
             <%: item.title %>
         </td>--%>
         <td>
             <%: item.description %>
         </td>
         <td>
             <input id="btn_comment" type="button" value="Add a Comment" />
         </td>
         <td>
             <div id="new_comment"></div></td>
     </tr>
 
 <% Next%>
 

---