gistfile1.js

 /* Utilities */

   if(!String.prototype.parseQueryString) {

     String.prototype.parseQueryString = function() {

            var mix = {};

            var vars = this.split(/[&;]/);   

                 if(vars.length > 0) {

                    vars.each(function(val){

                         var key = val.split("=");

                         if(key.length && key.length == 2) {

                            mix[key[0]] = key[1];
                         }
                    });   
                 }       

        return mix;   
     };
   }

   function getQueryStringValue(key) {
     
        try {
          return getQueryStringValues()[key];
        }catch(e){return null;}
   };

   function getQueryStringValues(){

        var win = document.location.href;

        //get query string
        var qs = win.split("?")[1];

        try{
           if(qs){return qs.parseQueryString();}
        }catch(e){return null;} 

   };

You shouldn't extend String.prototype.

Use https://github.com/sindresorhus/query-string instead.