Validating define xml
Regex queries are not equipped to break down HTML into its meaningful parts. Even enhanced irregular regular expressions as used by Perl are not up to the task of parsing HTML. HTML is a language of sufficient complexity that it cannot be parsed by regular expressions.
XML Schema, in contrast, overcomes this limitation by providing 44 built-in datatypes.HTML and regex go together like love, marriage, and ritual infanticide. The force of regex and HTML together in the same conceptual space will destroy your mind like so much watery putty.If you parse HTML with regex you are giving in to Them and their blasphemous ways which doom us all to inhuman toil for the One whose Name cannot be expressed in the Basic Multilingual Plane, he comes.DTD-validating parsers are most common, but some support XML Schema or RELAX NG as well.
The W3C XML Schema Datatype Specification defines numerous datatypes for validating the element content and the attribute value.The Document Type Definition (DTD) language, which is native to the XML specification, is a schema language that is of relatively limited capability, but that also has other uses in XML aside from the expression of schemas.