$(document).ready(function() {

                  $('#btn_<%=UserStuff.tag %>').click(function() {                    

                      var value = $('#<%#Eval("tag") %>twink').val();
                      something(value);                    
                  });
              });


              function something(theval) {

                alert(theval);

                  $.ajax({
                      type: "POST",
                      url: "/Default.aspx/MyMethod?something=" + theval,
                      data: "{}",
                      contentType: "application/json; charset=utf-8",
                      dataType: "json",
                      success: function(msg) {
                          alert(msg);
                      }
                  });
              }



-- my c# method is:


   public JsonResult MyMethod(string something)
    {
        JsonResult ret = new JsonResult();      

        return ret;
    }