docs: function (elements, attribute, value) {
              var foundElements = [], value = value || null;
              for (i = 0; i < elements.length; i++) {
                  // If the value parameter is set, return only the
                  // elements that has the given attribute value.
                  if (value !== null) {
                      if (elements[i].getAttribute(attribute) === value)
                          foundElements.push(elements[i]);
                  } else {
                      if (elements[i].getAttribute(attribute) !== null)
                          foundElements.push(elements[i]);
                  }
              }
  
              return foundElements;
          }