XML with correct syntax is "Well Formed" XML.
XML validated against a DTD is "Valid" XML.
A "Well Formed" XML document has correct XML syntax.
The syntax rules were described in the previous chapters:
A "Valid" XML document is a "Well Formed" XML document, which also conforms to the rules of a Document Type Definition (DTD):
The DOCTYPE declaration in the example above, is a reference to an external DTD file. The content of the file is shown in the paragraph below.
The purpose of a DTD is to define the structure of an XML document. It defines the structure with a list of legal elements:
If you want to study DTD, you will find our DTD tutorial on our homepage.
W3C supports an XML-based alternative to DTD, called XML Schema:
If you want to study XML Schema, you will find our Schema tutorial on our homepage.
To help you check the syntax of your XML files, we have created an XML validator to syntax-check your XML.
Please see the next chapter.
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