<dd>

<p>An [=accessible object=] in the <a>accessibility tree</a> and its descendants in that tree. It does not include objects which have relationships other than parent-child in that tree. For example, it does not include objects linked via <a class="specref" href="#aria-flowto">aria-flowto</a> unless those objects are also descendants in the <a>accessibility tree</a>.</p>

</dd>

<dt><dfn data-export="">Activation behavior</dfn></dt>

<dd>

<p>The action taken when an <a>event</a>, typically initiated by users through an input device, causes an element to fulfill a defined role. The role may be defined for that element by the host language, or by author-defined variables, or both. The role for any given element may be a generic action, or may be unique to that element. For example, the activation behavior of an <abbr title="Hypertext Markup Language">HTML</abbr> or <abbr title="Scalable Vector Graphics">SVG</abbr> <code>&lt;a&gt;</code> element shall be to cause the user agent to traverse the link specified in the <code>href</code> attribute, with the further optional parameter of specifying the browsing context for the traversal (such as the current window or tab, a named window, or a new window); the activation behavior of an <abbr title="Hypertext Markup Language">HTML</abbr> <code>&lt;input&gt;</code> element with the <code>type</code> attribute value <code>submit</code> shall be to send the values of the form elements to an author-defined <abbr title="Internationalized Resource Identifiers">IRI</abbr> by the author-defined <abbr title="Hypertext Transfer Protocol">HTTP</abbr> method.</p>