Currently I got the following request from one of the clients:

I need help creating specific conversion evens for my contest funnel. Very simple funnel. One event for visitors who did not opt in and one event for visitors that opted in.

It’s clear about the second event which the client wants to have (for the visitors that opted in) but why should an event be fired for visitors who did not opt-in? Will this be set as conversion? Sure, it will not be used as a conversion event. It will be used to configure an audience in order to retarget the visitors who did not opt-in.

It’s possible to use beforeunload JavaScript event in order to fire an event for visitors who did not opt-in. But this is not reliable because there are too many cases when such an event will fail to fire.

It's a much better idea to fire pageview and opt-in events only. Fortunately in Facebook it is possible to exclude the audience of opt-id from pageview in order to get the audience of users who did not opt-in.

In order to do this it’s necessary to configure pageview and opt-in event first and follow these steps to create the audience in Facebook:

  1. Navigate to Audiences
  2. Note: If you want to create an audience in other than your default account you will get redirected to Assets Library when changing the account. Fortunatly you can configure your custom audience starting from that page. Click Create Audience:

  3. If you already have audiences, click the Create Audience drop-down menu and select Custom Audience.
  4. If you don't have any audiences, you'll see audience creation buttons, rather than drop-down menus. Click Create a Custom Audience.
  5. Click Website traffic.

  6. Select People who visited specific web pages

  7. Type the full page url or page path

  8. Click Exclude people

  9. Select your opt-in event

  10. Type the name that describes your audience and click Create Audience

This is done!

This will be more accurate configuration than the one initially suggested by the client.