I'm learning how to do custom functions in XSLT. Every example I find seems to declare a custom namespace, e.g.
<xsl:stylesheet version="2.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
xmlns:mynamespace="http://whatever">
What I don't understand is what should go where I currently have 'http://whatever', and what does this do? Can't I use the default xsl namespace to make functions?
Thanks in advance for any help