Great XML Validator of W3Schools
Errors in XML documents will stop your XML applications.
The W3C XML specification states that a program should stop processing an XML document if it finds an error. The reason is that XML software should be small, fast, and compatible.
HTML browsers will display HTML documents with errors (like missing end tags).
With XML, errors are not allowed.
01 - http://www.w3schools.com/xml/xml_validator.asp 02 - http://www.freeformatter.com/xml-formatter.html#ad-output