rails，prototype和：afterFinish回调问题

Question

为什么这样做

<script type="text/javascript">
    var mycallback = function() {
      $('user_session_username').focus();
     };
</script>

page.visual_effect :appear, 'user-response', :afterFinish => "mycallback"

以下两个陈述都不起作用

page.visual_effect :appear, 'user-response', :afterFinish => "$('user_session_username').focus()" 

或

page.visual_effect :appear, 'user-response', :afterFinish => "$('user_session_username').focus" 

Answer 1

这是否有效：

page.visual_effect :appear, 'user-response', :afterFinish => "function(){$('user_session_username').focus()}"

注意： link_to_function适用于Rails 2.x但不适用于Rails 3.x. More info on this