function getQueryStringParams( query ) {
   var Params = {};
   if ( ! query ) {return Params;}// return empty object
   var Pairs = query.split(/[;&]/);
   for ( var i = 0; i < Pairs.length; i++ ) {
      var KeyVal = Pairs[i].split('=');
      if ( ! KeyVal || KeyVal.length != 2 ) {continue;}
      var key = unescape( KeyVal[0] );
      var val = unescape( KeyVal[1] );
      val = val.replace(/\+/g, ' ');
      Params[key] = val;
   }
   return Params;
}
 
 
Usage: 
 
var queryString = url.replace(/^[^\?]+\??/,'');
var params = getQueryStringParams(queryString);