using :onkeyup=> for a f.text_field using jqeury
===

I have a partial with the below code:

    <%= form_for :subString_typed, :controller => "deployment_group", :remote=> true, :method => "get", :url => {:action => "show_workflow_list"}, :html => {:id => "subString_form"} do |f| %>
    			<%= f.label :Substring %> <%= f.text_field :subString, :onkeyup => "show_alert()" %>
    <%end%>

and down below in the same form, i wrote the javascript function for show_alert() like this:

    <script type="text/javascript">   
    function show_alert()
    			{
    				$('#subString_typed_subString').change(function(){$('#subString_form').submit();});
    			}
    			</script> 
Will the above code submit the substring form when i type in a letter in the substring text field?
It does not work for me. Is my jquery code wrong? My id's are correct in the jqeury code, however i think im using the wrong function (.change) for the text field.
Please help