code: function getUniqueItemId(selector) {
  
              var base_id = selectorToId(selector),
                  id = base_id,
                  numeric_suffix = 0;
  
              while (used_item_ids.indexOf(id) !== -1) {
                  id = base_id + "_" + ++numeric_suffix;
              }
  
              used_item_ids.push(id);
              return id;
          }
docs: Converts selector to ID and assures it is unique
  @param {string} selector
  @returns {string}
  @todo dry?