Unified mouse/touch/pen — `pointerdown` vs separate touch handlers.

Performance Metrics

Pointer events model

<h2>Summary</h2>
<p><code>aria-live="polite|assertive"</code> queues announcements — polite waits for idle; assertive interrupts. Too chatty live regions overwhelm users. <code>aria-atomic</code>, <code>aria-relevant</code> control granularity. Prefer visible status; live regions for async updates (toast, validation).</p>
<h2>Code example</h2>
<pre><code class="language-html">&lt;div aria-live="polite" aria-atomic="true" id="status"&gt;
  &lt;!-- Updated after async save --&gt;
&lt;/div&gt;
&lt;script&gt;
  statusEl.textContent = 'Saved successfully';
&lt;/script&gt;
</code></pre>
<h2>Key points</h2>
<ul>
<li><code>aria-live="polite|assertive"</code> queues announcements — polite waits for idle; assertive interrupts.</li>
<li>Too chatty live regions overwhelm users.</li>
<li><code>aria-atomic</code>, <code>aria-relevant</code> control granularity.</li>
<li>Prefer visible status; live regions for async updates (toast, validation).</li>
</ul>
<h2>Further reading</h2>
<ul>
<li><a href="https://developer.mozilla.org/en-US/docs/Web/Accessibility/ARIA/ARIA_Live_Regions">ARIA live regions</a></li>
<li><a href="https://developer.mozilla.org/en-US/docs/Web/Accessibility/ARIA/Attributes/aria-live">aria-live</a></li>
</ul>
<h2>Related concepts</h2>
<ul>
<li><a href="/blogs/level-9-accessibility-tree">Accessibility tree</a></li>
<li><a href="/blogs/level-9-pointer-events-model">Pointer events model</a></li>
</ul>


`aria-live="polite|assertive"` queues announcements — polite waits for idle; assertive interrupts.

ARIA live regions internals

Parallel tree to DOM — roles, names, states exposed to assistive tech.