$el

$el is a magic property that can be used to retrieve the current DOM node.

<button @click="$el.innerHTML = 'Hello World!'">Replace me with "Hello World!"</button>

<div class="demo">
    <div x-data>
        <button @click="$el.textContent = 'Hello World!'">Replace me with "Hello World!"</button>
    </div>
</div>