How to use onsubmit in remote_form_for.....?

Rails Rails I18n
1

I want to check whether textfield is empty or not at onsubmit event of
form, but it is not working.
Can any one tell me how to check empty textfield on remote_form_for’s
onsubmit event???

my code is --------------->

<%remote_form_for(:comments, @comment, :url => @commentUrl, :html =>
{:method => :post, :onsubmit => ‘if ($(“comments_comment”).value == “”)
{showNotificationMessage(“Please enter comment”, Notification.Error,
comments_comment); return false;}’}) do |f| %>
<%= f.text_area “comment”, :rows => 2,
:style=>“width:100%;padding-right:8px;margin-top:8px;margin-bottom:8px;”
%>

  <%=submit_to_remote f, "Add comment",
    :url => @commentUrl,
    :update => { :success => divID, :failure => divID }%>
<%end%>

‘onsubmit’ is not excuted during form submit.
Any one can help me.