gistfile1.txt

      calculateUrl: function(){
        var original_location = window.location.href;
        var has_slide_param = original_location.match(/slide=/);
        var has_name_param = original_location.match(/name=/);
        var has_query_param = original_location.match(/\?/);
        var guid = this.collection.get(this.current_page)[0].guid,
            new_url;

        if(has_slide_param){
          new_url = original_location.replace(/slide=[^&$]+/,"slide="+guid);
        }else if(has_query_param){
          new_url = (window.location +'&slide='+ guid);
        }else{
          new_url = (window.location +'?slide='+ guid);
        }

        new_url = new_url.replace(/[\?&]name=[^&$]+/,'');
        if(this.multi) {
          new_url += '&name=' + this.name;
        }