XML in a Nutshell, 3rd Edition

XPointers in Links

Obviously, what an XPointer points to depends on which document it’s applied to. This document is specified by the URL that the XPointer is attached to. For example, if you wanted a URL that pointed to the first name element in the document at http://example.org/people.xml, you would type:

http://example.org/people.xml#xpointer(//name[position( )=1])

If the XPointer uses any characters that are not allowed in URIs—for instance, the less than sign <, the double quotation mark “, or non-ASCII letters like é—then these must be hexadecimally escaped as specified by the URI specification before the XPointer is attached to the URI. That is, each such character is replaced by a percent sign followed by the hexadecimal value of each byte in the character in the UTF-8 encoding of Unicode. Thus, < would be written as %3C, " would be written as %22, and é would be written as %C3%A9.

In HTML, the URLs used in a elements can contain an XPointer fragment identifier. For example:

<a href = "http://www.example.org/people.xml#xpointer(//name[1])">
  The name of a person
</a>

If a browser followed this link, it would likely load the entire document at http://www.example.org/people.xml and then scroll the window to the beginning of the first name element in the document. However, no browsers yet support the XPointer xpointer scheme, so the exact behavior is open for debate. In some situations it might make sense for the browser to show only the specific element node(s) the XPointer ...