Can someone explain what the xml:base attribute is used for in XHTML5?_问答_开发者

Can someone explain what the xml:base attribute is used for in XHTML5?

开发者 https://www.devze.com 2023-01-25 19:04 出处：网络

I was won开发者_StackOverflow社区dering what does the xml:base attribute do and what are it\'s values in XHTML5. and does the xml:base attribute have any restrictions?Documentation for the xml:base ca

相关专题：xml

I was won开发者_StackOverflow社区dering what does the xml:base attribute do and what are it's values in XHTML5. and does the xml:base attribute have any restrictions?

Documentation for the xml:base can be found here. It allows a redefinition of the base address used by relative addresses in child elements.

This is the example for that source,

<?xml version="1.0"?>
<doc xml:base="http://example.org/today/"
     xmlns:xlink="http://www.w3.org/1999/xlink">
  <head>
    <title>Virtual Library</title>
  </head>
  <body>
    <paragraph>See <link xlink:type="simple" xlink:href="new.xml">what's
      new</link>!</paragraph>
    <paragraph>Check out the hot picks of the day!</paragraph>
    <olist xml:base="/hotpicks/">
      <item>
        <link xlink:type="simple" xlink:href="pick1.xml">Hot Pick #1</link>
      </item>
      <item>
        <link xlink:type="simple" xlink:href="pick2.xml">Hot Pick #2</link>
      </item>
      <item>
        <link xlink:type="simple" xlink:href="pick3.xml">Hot Pick #3</link>
      </item>
    </olist>
  </body>
</doc>

In this case the "What's new" link points to http://example.org/today/new.xml, which is the doc element's xml:base absolute address plus the xlink:href attribute's relative address.

The olist element's xml:base address redefines the base address, using the domain of doc's xml:base but changing the path. So the subsequent links are relative to http://example.org/hotpicks/.