Devuelve el número de caracteres en que el foco de la selección es colocado dentro de focusNode.
sel.focusOffset
Este número está basado en cero. Si la selección termina con el primer carácter en focusNode, el número devuelto será 0.
SelectionSelection.addRange()Selection.collapse()Selection.collapseToEnd()Selection.collapseToStart()Selection.containsNode()Selection.deleteFromDocument()Selection.extend()Selection.getRangeAt()Selection.modify()Selection.removeAllRanges()Selection.removeRange()Selection.selectAllChildren()Selection.selectionLanguageChange()Selection.toString()AttrCDATASectionCharacterDataChildNodeCommentCustomEventDOMConfigurationDOMErrorDOMErrorHandlerDOMExceptionDOMImplementationDOMImplementationListDOMImplementationRegistryDOMImplementationSourceDOMLocatorDOMObjectDOMParserDOMStringDOMTimeStampDOMTokenListDOMUserDataDocumentDocumentFragmentDocumentTypeElementElementTraversalEntityEntityReferenceEventEventTargetHTMLCollectionMutationObserverNodeNodeFilterNodeIteratorNodeListNonDocumentTypeChildNodeProcessingInstructionPromiseResolverRangeTextTextDecoderTextEncoderTimeRangesTreeWalkerTypeInfoUserDataHandlerXMLDocument