为什么我写的DTD不起作用?
xml文本如下:
<?xml version="1.0" encoding="GB2312" ?>
<!DOCTYPE library SYSTEM "library.dtd">
<library>
<book>
<name>计算机入门</name>
<author>张三</author>
<price>12.5</price>
</book>
<book>
<name>word</name>
<author>李四</author>
<price>12.5</price>
</book>
<book>
<name>vb</name>
<author>刘二</author>
<price>12.5</price>
</book>
</library>
dtd:
<!ELEMENT library (book)+>
<!ELEMENT book (name,author,price,publish+)>
<!ELEMENT name (#PCDATA)>
<!ELEMENT author (#PCDATA)>
<!ELEMENT price (#PCDATA)>
<!ELEMENT publish (#PCDATA)>
为什么我的xml文本里没有publish元素,也不报错?