Devuelve el número de caracteres en que el ancla de la selección es colocada dentro de anchorNode.
sel.anchorOffset
Este número está basado en cero. Si la selección empieza con el primer carácter en anchorNode, 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