Allow html in opt-out link

So basically i’m refering to case, where tracking can be disabled by simply using code like:
<a href="javascript:gaOptout()">Click here to opt-out of Google Analytics</a>

it’s from official google dev page:
https://developers.google.com/analytics/devguides/collection/gajs/#disable

Correct me if i’m wrong, but isn’t much more simple than sending user to another page/website to opt-out?