Add parameter in url with javascript

My problem:

I have a property listing to be sorted every time a filter is done, the way I am doing when the sort option is selected, the whole content is sorted, not the current one. How do I keep the url that is in the address bar without losing the current parameters and add the parameter (& order = xxx)?

JSCODEFORORDERING

$("select.ordenacao").change(function() {
        $("select.ordenacao").each(function() {
          str = $( this ).val();
          //alert(str);
            //$("#ordenar").submit();
             location.href='lista?ctgr='+getValueQS("ctgr")+'&city='+getValueQS("city")+'&s='+getValueQS("s")+'&d='+getValueQS("d")+'&v=0'+'&vmin='+getValueQS("vmin")+'&vmax='+getValueQS("vmax")+'&submit='+getValueQS("submit")+'&ordenacao='+str;
        });
    });
function getValueQS(key) {  
      return unescape(window.location.search.replace(new RegExp("^(?:.*[&\?]" + escape(key).replace(/[\.\+\*]/g, "\$&") + "(?:\=([^&]*))?)?.*$", "i"), "$1"));  
    } 

I do not know if I'm doing it correctly, because some parameters of the above function is passed the value, others are blank by breaking the query from my sql.