dom w3c dom DOMImplementation w3c dom DocumentType domimplementationimpl coredomimplementationimpl domimplementation domimplementationimpl singleton domimplementationimpl domimplementation getdomimplementation singleton hasfeature feature version super.hasfeature feature version anyversion version version.length feature.startswith feature feature.substring feature.equalsignorecase anyversion version.equals feature.equalsignorecase anyversion version.equals feature.equalsignorecase anyversion version.equals feature.equalsignorecase anyversion version.equals feature.equalsignorecase anyversion version.equals coredocumentimpl createdocument documenttype doctype documentimpl doctype