code: protected final T setEmptyAttributeValueAsBoolean(String attributeName, boolean value) {
      if (value) {
        setAttribute(attributeName, attributeName.toLowerCase());
      }
      else {
        removeAttribute(attributeName);
      }
      return (T)this;
    }
docs: Sets "empty" attribute value as boolean (i.e. for "checked" attribute).
  @param attributeName Attribute name
  @param value Attribute value as boolean
  @return Self reference