function parseQueryString() {
   str = location.search;
   var query = str.charAt(0) == '?' ? str.substring(1) : str;
   var queryString = new Object();
   if (query) {
      var fields = query.split('&');
      for (var f = 0; f < fields.length; f++) {
         var field = fields[f].split('=');
         var fieldName = unescape(field[0].replace(/\+/g, ' '));
         var fieldValue = (field[1])?unescape(field[1].replace(/\+/g, ' ')):'';
         queryString[fieldName] = fieldValue;
      }
   }
   return queryString;
}