Hiding web elements for known person

First — for the lurkers — we mean “(a) the current pageview or (b) the stored Munchkin cookie in the current browser session is directly associated with one existing person in your Marketo instance.”

The answer is to use Known Visitor HTML (KV HTML) and a hidden form. When the form is ready (whenReady) you can check if the KV HTML is present in the DOM; alternately (though I find this a bit messy) you can put JS in the KV HTML block itself. Either mark up the body tag with a special CSS class or take any other action you want using JS.

Naturally this assumes the elements on the page have already been prepared to be shown/hidden using this method. You might even be using a client-side template framework and not inject certain elements unless you’re in known mode.