Correct microdata markup for breadcrumbs

I would do something like :

<div itemscope itemtype="http://data-vocabulary.org/Breadcrumb">
    <a href="#" itemprop="url"><span itemprop="title">Homepage</span></a>
    <div itemprop="child" itemscope itemtype="http://data-vocabulary.org/Breadcrumb">
        <a href="#" itemprop="url"><span itemprop="title">Child-A</span></a>
    </div>
    <div itemprop="child" itemscope itemtype="http://data-vocabulary.org/Breadcrumb">
        <a href="#" itemprop="url"><span itemprop="title">Child-B</span></a>
    </div>
</div>

Tested on : https://search.google.com/structured-data/testing-tool

Use Schema.org as data-vocabulary.org is abandoned.

There were a few markups when the idea came up. But since then the standard has arrised as being Schema.org. It's of course supported by Google and given in its examples (one is BreadCrumbs).

Modern (2019) correct breadcrumbs Microdata markup is like provided below.

And if you want to complain best practices do not make the last breadcrumb item as a link on your page - you can use <span> instead of <a> in a such manner:

<ol itemscope itemtype="http://schema.org/BreadcrumbList">
  <li itemprop="itemListElement" itemscope itemtype="http://schema.org/ListItem">
    <a itemscope itemtype="http://schema.org/Thing" itemprop="item" href="/" itemid="/">
      <span itemprop="name">Root page</span>
    </a>
    <meta itemprop="position" content="1" />
  </li>
  <li itemprop="itemListElement" itemscope itemtype="http://schema.org/ListItem">
    <a itemscope itemtype="http://schema.org/Thing" itemprop="item" href="/category" itemid="/category">
      <span itemprop="name">Category page</span>
    </a>
    <meta itemprop="position" content="2" />
  </li>
  <li itemprop="itemListElement" itemscope itemtype="http://schema.org/ListItem">
    <span itemscope itemtype="http://schema.org/Thing" itemprop="item" itemid="/category/this-page">
      <span itemprop="name">This page</span>
    </span>
    <meta itemprop="position" content="3" />
  </li>
</ol>

This code is fully compliant to BreadcrumbList (see also that item's id is required) and passes Google validation on https://search.google.com/structured-data/testing-tool excellent.