js构建sql查询时的问题

Question

        for (var i=0; i<itemCollection.length; i++)
        {
            oItem = new Item(itemCollection(i));
            if (i==0)
            {
                sqlString += oItem.id + "=" + oItem.selectedValue;
            }
            else
            {
                sqlString += "&" + oItem.id + "=" + oItem.selectedValue;
            }
        }