HttpServletRequest + DWR giving me null values.

hi y'all,
could anyone please tell me how DWR is used with HttpServletRequest, i tried this,

class DWRDemo
////
public String getUsername(HttpServletRequest request) {
    HttpServletRequest request = wctx.getHttpServletRequest();
    return request.getParameter("username");
}
assuming i'v got html file with this attribute
<input type="text" name="username" size="10"> and the javaScript,

    <script>
                function username() {
          DWRDemo.getUsername(showSalutation);
                }

        </script>

Am i missing sumthing here. I v been searching for days now...but i keep on getting the same people having similar problem and getting the not working responses.

Please read study my problem before you start using your valuable time that i will highly appreciate be you start replying.

Thanks in advance.

lvcster.