XSLT namespaces URL

Question

What does a namespace do in XSLT when a url is provided such as:

xmlns:xsl="http://www.w3.org/1999/XSL/Transform"

does this attempt to make a connection to the internet?

Answer 1

When you conduct an XSLT transformation, the XSLT engine validates the XSLT file. It performs many checks, such as the root element being named stylesheet, etc. The engine must also be able to discern literal result elements (like <table>) from XSLT-specific elements (like <xsl:stylesheet>).

An element is recognized as XSLT-specific when it resides in the XSLT namespace. The value of the URI you posted (http://www.w3.org/1999/XSL/Transform) is simply a convention that makes it clear we're talking about XSLT. The prefix being defined (xsl) is the prefix used in the XSLT file to qualify the XSLT elements. You can use another prefix if you choose, provided you map it to the XSLT namespace.

Note that it's actually just a URI (an identifier), not a URL (a locator). There is no HTTP request to locate anything, it just identifies an abstract concept (in this case "XSLT").

Answer 2

No; it just so happens that the specification for XML Namespaces (see W3C XSL Namespace specifications) are URI's.

They work in exactly the same way that namespaces in other languages do; they help uniquely identify things with the same names but in different contexts.

You can prove that no attempt is made to retrieve the resource by using a HTTP Monitor on your machine while loading or using the XSL Transformation - this answer has many good suggestions.

Answer 3

No. Whatever the namespace is in a xsd, an xslt or any other xml file, there is no internet request.

The namespace is used to qualified your xml element.