function set_order(){	
	newOrder=document.getElementById("products_order")[document.getElementById("products_order").selectedIndex].value;
	newOrder = (newOrder=="DESTACADOS"?"":newOrder);
	go("order_by", newOrder); 
}



function go(par, newValue){
	addQSParam("from", "");
	addQSParam(par, newValue);
	location.href = getURL();
}

var queryString = oldUrl.substr(oldUrl.indexOf("?"));
var oldPath = oldUrl.substr(0,oldUrl.indexOf("?"));
var NOT_FOUND = -1;
function addQSParam(par, newValue){
    //si no esta, lo agrego
    pos = queryString.indexOf(par+"=");
    if (pos == NOT_FOUND){
        //solo agrego si hay valor
                if ( newValue.length > 0 ) {
                        if (queryString.indexOf("?")==NOT_FOUND)
                                queryString     += "?";
                        else
                                queryString     += "&";
                       queryString     += par+"="+escape(newValue);
                }
    } else {
        //si esta, lo reemplazo
        start = pos-1;
       end = queryString.indexOf("&", pos+1);
                if (end == NOT_FOUND)
                    toReplace = queryString.substr(start);
                else
                    toReplace = queryString.substr(start, end-start);

               if ( newValue.length > 0 )
                        newString = toReplace.substr(0,1)+par+"="+escape(newValue);
                else
                        newString = "";

        queryString = queryString.replace(toReplace,newString);
    }
}



function getURL(){

    return oldPath+queryString;

}