该点及下面派生的所有点的全部信息,只读如果要求book点的xml,返回“<book level="1"><Name>c++</Name><Price>20</Price><info><k>1</k></info><info><k>2</k></info></book>”,如果Name的xml,返回“<Name>c++</Name>”
2.1.4 text
Represents the text content of the node or the concatenated text representing the node and its descendants. Read/write
该点及下面派生的所有点的全部节点值,可读可写
<price>20</price>
则text为20
"Name"节点的text为"c++"