JSP Bean in javascript lead to blank page

Hello everyone !
I'm developping a JSF application. My pages are JSP extension and i have some javascript scripts inside.
My situation is simple but can't solve it. I have to fill in javascript tabs thanks to values provided by my beans.

Here is my code : ( i replaced my true classes ^^)

Code:

<%@page language="java" import="com.test.Toto"%>
<jsp:useBean id="totoManager" class="com.test.TotoManager"></jsp:useBean>
...
 <script type="text/javascript">
  var categories;
  var data;
  var count;
<% for (com.test Toto: totoManager.getJokes()) { %>
                  categories.push(<%= toto.getCategory() %>);
                  data.push({
                     title: <%= toto.getTitle() %>,
                     joke:<%= toto.getText() %>       
                  });
                  count++;
  <% } %>
</script>

Here is the result i'd like to obtain after the loop :

Code:

            var categories = ['Poo', 'Funny', 'Toto's Mother'],       var data = [{              title: 'blabla',             joke: 'wonderful joke',          }, {             title: 'foo',             joke: 'so funny',          }]

If i remove the script the page loads correctly, but with the script, it remains blank, with no source code ...
So i might have a problem calling my bean !

Thanks for helping