1. An XML parser calling an external XML validator, said XML parser comprising: an XML receiver configured to receive an XML document from an XML application; an external XML validator caller configured to request the external XML validator to verify the validity of the XML document and to receive an answer to the request; and a DOM/SAX tree generator configured to generate, if said external XML validator caller receives an answer indicating that the XML document is valid, a DOM/SAX tree from the XML document and to transmit the DOM/SAX tree to the XML application.