The XML specification supports a very specific character set. Characters that fall outside of the specified ranges result in a parser error whenever the XML string is parsed.
The XML specification allows for the use of various encodings. UTF-8 or UTF-16 are typically expected; however, it is recognised that other encodings exist in the world: Correctly encoding XML allows for portable applications.
XPATH has a rich set of functions that can be used to evaluate, manipulate and otherwise traverse an XML document.
XPATH allows the use of wildcards to write more robust path expressions where the use of specific path expressions is either impossible or undesirable.
XPATH path expressions are used to refer to specific nodes or values in an XML document.
XSL provides support for conditional patterns, statements and values – much the same as any other programming language. The appropriate application of the available XSL functions allows you to implement each pattern.
The XSLT <xsl:otherwise> element provides a default value/evaluation within the scope an <xsl:choose> conditional evaluation.
The XSLT <xsl:when> element provides a conditional test to use against the contents of an XML file within the scope a larger <xsl:choose> conditional evaluation.
The XSLT <xsl:choose> element provides a complex conditional test to use against the contents of an XML file.
The XSLT <xsl:if> element provides a simple conditional test to use against the contents of an XML file.