DOMCharacterData->substringData Extracts a range of data from the node &reftitle.description; stringDOMCharacterData->substringData intoffset intcount Returns the specified substring. If the sum of offset and count exceeds the length, then all 16-bit units to the end of the data are returned. Throws DOMException if offset is negative or greater than the number of 16-bit units in data, or if count is negative.