HTMLDocument is an abstract interface of the DOM which provides access to special properties and methods not present by default on a regular (XML) document.
Its methods and properties are included in the document page and listed separately in their own section in the above linked DOM page.
HTMLDocumentBeforeUnloadEventDOMStringMapDataTransferDragEventErrorEventGlobalEventHandlersHTMLAnchorElementHTMLAreaElementHTMLAudioElementHTMLBRElementHTMLBaseElementHTMLBaseFontElementHTMLBodyElementHTMLButtonElementHTMLCanvasElementHTMLContentElementHTMLDListElementHTMLDataElementHTMLDataListElementHTMLDialogElementHTMLDivElementHTMLElementHTMLEmbedElementHTMLFieldSetElementHTMLFormControlsCollectionHTMLFormElementHTMLFrameSetElementHTMLHRElementHTMLHeadElementHTMLHeadingElementHTMLHtmlElementHTMLIFrameElementHTMLImageElementHTMLInputElementHTMLIsIndexElementHTMLKeygenElementHTMLLIElementHTMLLabelElementHTMLLegendElementHTMLLinkElementHTMLMapElementHTMLMediaElementHTMLMetaElementHTMLMeterElementHTMLModElementHTMLOListElementHTMLObjectElementHTMLOptGroupElementHTMLOptionElementHTMLOptionsCollectionHTMLOutputElementHTMLParagraphElementHTMLParamElementHTMLPictureElementHTMLPreElementHTMLProgressElementHTMLQuoteElementHTMLScriptElementHTMLSelectElementHTMLShadowElementHTMLSourceElementHTMLSpanElementHTMLStyleElementHTMLTableCaptionElementHTMLTableCellElementHTMLTableColElementHTMLTableDataCellElementHTMLTableElementHTMLTableHeaderCellElementHTMLTableRowElementHTMLTableSectionElementHTMLTextAreaElementHTMLTimeElementHTMLTitleElementHTMLTrackElementHTMLUListElementHTMLUnknownElementHTMLVideoElementHashChangeEventHistoryImageDataLocationMessageChannelMessageEventMessagePortNavigatorNavigatorGeolocationNavigatorIDNavigatorLanguageNavigatorOnLineNavigatorPluginsPageTransitionEventPluginPluginArrayPopStateEventPortCollectionRadioNodeListTransferableValidityStateWebVTTWindowWindowBase64WindowEventHandlersWindowTimers