paramtoggler

(function() {

   var params = /(?:&|\?)(.+)/g.exec(window.location.href);
   var paramsObj = {};
   if (params && Object.keys(params).length) {
      params[1].split('&').forEach(function(strPair) { 
      var splitPair = strPair.split('=');
      paramsObj[splitPair[0]] = splitPair[1];
     });
   }

   function applyParams(){
      var url = window.location.href.match(/^[^&|?]+(?:[^&|?])/g);
      var isFirst = true;
      for (var key in paramsObj) {
         var ampersand = isFirst ? '?' : '&';
         var value = paramsObj[key];
         if (value) {
           url += ampersand + key + '=' + paramsObj[key];
         } else {
           url += ampersand + key;
         }
         isFirst = false;
      }
      return url;
   }

   function getOnOffState(currentValue){
      return (currentValue == 'on') ? 'off' : 'on';
   }

   window.addParam = function(key, value){
      var currentValue = paramsObj[key];
      var value = value || getOnOffState(currentValue);
      paramsObj[key] = value;
      return applyParams();
   }

   window.getCookie = function(key){
      var keyValue = document.cookie.match('(^|;) ?' + key + '=([^;]*)(;|$)');
      return keyValue ? keyValue[2] : null;
   }

   document.cookie = 'paramtoggler=' + escape(data);

})();