add support to same key occurred multi times

parseQuerystring.jquery.js

jQuery.extend({
  parseQuerystring: function(){
    var nvpair = {};
    var qs = window.location.search.replace('?', '');
    var pairs = decodeURI(qs).split('&');
    $.each(pairs, function(i, v){
      var pair = v.split('=');
      var key = pair[0], value = pair[1];
      if(key in nvpair){
          if(!$.isArray(nvpair[key])){ nvpair[key] = $.makeArray(nvpair[key]);}
          nvpair[key].push(value);
      } else {
          nvpair[key] = value;
      }
    });
    return nvpair;
  }
});