ml">virtual DOM node</a> structure.</p>
<p>The <strong>Required</strong> column indicates whether an argument is required or optional. If an argument is optional, you may set it to <code>null</code> or <code>undefined</code>, or omit it altogether, such that the next argument appears in its place.</p>
<hr>
<h3 id="optional-arguments"><a href="#optional-arguments">Optional arguments</a></h3>
<p>Function arguments surrounded by square brackets <code>[ ]</code> are optional. In the example below, <code>url</co