link_to_remote question

I have the simple view page:

<div id="test1"></div>
<%= link_to_remote "Turn on Alert", :url => {:controller => "alerts",
:action => "new"} :update => "test1" %>

Then in my controller I simply do

if request.xhr?
  render :text => "AJAX Called"
else
  redirect_to :back
end

It's hitting the request.xhr? block as I had a logger.info statement
there. However the "test1" div is not saying "AJAX Called". Nothing
appears.

Help?

One thing I forgot to add, I have a nested div actually b/c my layout
has a div. So the above is really

<div id="main">
<div id="test1"></div>
</div>

Could this be the problem?