HTML Element nodeType 定义

const unsigned short ELEMENT_NODE = 1; 
const unsigned short ATTRIBUTE_NODE = 2; 
const unsigned short TEXT_NODE = 3; 
const unsigned short CDATA_SECTION_NODE = 4; 
const unsigned short ENTITY_REFERENCE_NODE = 5; 
const unsigned short ENTITY_NODE = 6; 
const unsigned short PROCESSING_INSTRUCTION_NODE = 7; 
const unsigned short COMMENT_NODE = 8; 
const unsigned short DOCUMENT_NODE = 9; 
const unsigned short DOCUMENT_TYPE_NODE = 10; 
const unsigned short DOCUMENT_FRAGMENT_NODE = 11; 
const unsigned short NOTATION_NODE = 12;