attributedefaultlegal

下载来的一个看图软件的源代码

<?xml version="1.0"?>
<!DOCTYPE doc [
<!ELEMENT doc (#PCDATA)>
<!ATTLIST doc At NMTOKEN "$$$">
<!ATTLIST doc Ok NMTOKEN "1abc_2">
<!ATTLIST doc bad IDREF "1abc_2">
<!ATTLIST doc ok2 IDREF "abc_2">
<!ATTLIST doc bad2 IDREFS "abc:1 1abc_2">
<!ATTLIST doc ok3 IDREFS "abc:1 a1bc_2">
]>
<doc val="v1"/>