event.queryString is appended twice in url

[pandikamal]

hi, this is my code:

show click to play

$.address.change(function(event){

        var qstring = '';
      if( event.queryString != '')
        qstring =  event.queryString;
   var url = $.address.state() + event.path + qstring;
 load_page(url,'div#inside');

});

first i click show, the url is http://localhost/rw2011/?show_types=show, then next i click to play, the url is http://localhost/rw2011/player-list?id=57?show_types=todays_show

please help me.