nodeType的12种类型

// NodeType
    const unsigned short      ELEMENT_NODE                   = 1;   元素节点
    const unsigned short      ATTRIBUTE_NODE                 = 2;   属性节点
    const unsigned short      TEXT_NODE                      = 3;   文本节点
    const unsigned short      CDATA_SECTION_NODE             = 4;   CDATA 区段
    const unsigned short      ENTITY_REFERENCE_NODE          = 5;   实体引用元素
    const unsigned short      ENTITY_NODE                    = 6;   实体
    const unsigned short      PROCESSING_INSTRUCTION_NODE    = 7;   表示处理指令
    const unsigned short      COMMENT_NODE                   = 8;   注释节点
    const unsigned short      DOCUMENT_NODE                  = 9;   最外层的Root element,包括所有其它节点
    const unsigned short      DOCUMENT_TYPE_NODE             = 10;   <!DOCTYPE………..>
    const unsigned short      DOCUMENT_FRAGMENT_NODE         = 11;   文档碎片节点
    const unsigned short      NOTATION_NODE                  = 12;   DTD 中声明的符号节点