Escape or unescape characters from input XML string.
The following characters are reserved in XML and must be replaced with their corresponding entities in XML:
What is XML ?
XML is a markup language based on Standard Generalized Markup Language (SGML)
used for defining markup languages. XML's primary function is to create formats for data
that is used to encode information for documentation, database records, transactions and
many other types of data.
What is XML Escaping?
XML Escaping provides escape facilities for including characters that are problematic to include directly.
The special characters are key syntax markers and may never appear in content outside a CDATA section.
Some character encodings support only a subset of Unicode. For example, it is legal to encode an XML document in ASCII, but ASCII lacks code points for Unicode characters.
It might not be possible to type the character on the author's machine.
Some characters have glyphs that cannot be visually distinguished from other characters, such as the non-breaking space ( ) " " and the space ( ) " ", and the Cyrillic capital letter A (А) "A" and the Latin capital letter A (A) "A".