问个jQuery无刷新评论的问题, $.ajax 提交获取不到数据

<div name="post_box" class="post_box">
<textarea class="t_b_reply" id="comment_content_{$v[id]}" autocomplete="off" name="content"></textarea>
<a id="post_comment_submit_{$v[id]}" class="button primary fr" href="javascript:;" onclick="postComment({$v[id]});return false;">发表评论</a>
</div><p> </p>

function postComment(joke_id){
var content = $('#comment_content_' + joke_id).val();
var id = joke_id;
  $.ajax({ 
    type: "POST", 
    url: "index.php?a=public_postcomment", 
    data: "id="+id+"&content="+content
  }); 
};

是否JQ的ajax方法写错了,点击发表评论后,php获取不到数据