 attributes are strictly required, always include a hyphen in the
value to ensure it does not match the JavaScript identifier syntax, e.g. use
<code>user-profile</code> rather than just <code>profile</code> or <code>userProfile</code>.</p>

<p>When an element has an <code>id</code> attribute, browsers will make that available as a
<a href="https://html.spec.whatwg.org/multipage/window-object.html#named-access-on-the-window-object">named property on the global <code>window</code> prototype</a>,
which may cau