View the original community article here
Last tested: Aug 21, 2019
This is meant for anyone who needs are looking for a working example and an explanation on changing filters of embedded private looks with javascript events. Link here:
https://gist.github.com/SidneyJrLooker/47b69a4ffe7cc7ef903765a51a442e6d

If you want to test it, you will need to host your html file on your localhost.
Documentation for making changes to the iframes with javascript events: https://docs.looker.com/reference/embedding/embed-javascript-events#making_changes_to_the_iframe
This content is subject to limited support.