问题
I'm new to XML. I'm confused how a DTD document validates an XML document. Below is my code and please correct me if I am wrong.
<?xml version="1.0" encoding="iso-8859-1"?>
<!DOCTYPE note
[
<!ELEMENT note (to,from,heading,body)>
<!ELEMENT to (#PCDATA)>
<!ELEMENT from (#PCDATA)>
<!ELEMENT heading (#PCDATA)>
<!ELEMENT body (#PCDATA)>
]>
<note>
<to>Tove</to>
<rom>Jani</rom> // Here i've miss-spelled the tag <from> but still not getting error
<heading>Reminder</heading>
<body>Don't forget me this weekend!</body>
</note>
I know that a DTD is used to validate the XML data. There is an element name <form>. I've just changed the spelling of <form> to <rom> but still did not get any error message in my browser. I'm stuck at this point.
回答1:
Welcome to the XML community.
You will need to find and use a validating parser for your XML; if you want to use a Web browser, you may be disappointed. Older versions of Internet Explorer validate XML against a DTD by default; newer versions don't (but I believe that you can configure them to do so if you can figure out how). Mozilla-based browsers don't have a validating XML parser at all.
Most people who use XML seriously end up using XML-specific tools for validation. Among my favorites for command-line validation are
xmllint (the command-line interface to libxml2, which is part of the Gnome project but is also usable outside Gnome)
rxp (by Richard Tobin of the University of Edinburgh)
Xerces J, Xerces C (these are Apache projects)
There are also XML-aware editors which offer integrated validation from within the editor (sometimes from your choice of several parsers).
来源：https://stackoverflow.com/questions/14014307/validation-of-an-xml-document-using-a-dtd-document