资料向：nodeType,nodeName和nodeValue

nodeType：

• Node.ELEMENT_NODE == 1
• Node.ATTRIBUTE_NODE == 2
• Node.TEXT_NODE == 3
• Node.CDATA_SECTION_NODE == 4
• Node.ENTITY_REFERENCE_NODE == 5
• Node.ENTITY_NODE == 6
• Node.PROCESSING_INSTRUCTION_NODE == 7
• Node.COMMENT_NODE == 8
• Node.DOCUMENT_NODE == 9
• Node.DOCUMENT_TYPE_NODE == 10
• Node.DOCUMENT_FRAGMENT_NODE == 11
• Node.NOTATION_NODE == 12

nodeName：

nodeName is a read-only attribute.

Note that tagName property could have been used instead, since nodeName has the same value as tagName for an element. Bear in mind, however, that nodeName will return#text for text nodes while tagName will return undefined.

nodeValue：

When nodeValue is defined to be null, setting it has no effect.

nodeValue一般只用来设置文本节点的值。如果要刷新属性节点的值，一般使用setAttribute().  

来源：https://developer.mozilla.org/en/nodeType

https://developer.mozilla.org/en/nodeName

https://developer.mozilla.org/en/nodeValue