It makes more sense to have a class which handles a <linkGrp> element to be called ImtLinkGrp, so I've refactored the code and changed the file names. I've also made the namespace handling more sophisticated, so if the ImtLink or ImtLinkGrp classes have an assigned namespace, then they use createElementNS() to write themselves, but if not, they use createElement(). Finally, I've made ImtLink more sophisticated in its handling of linkType and nsUri properties: if it has a parent ImtLinkGrp, then it uses the properties from that, but if not it uses its own.