My Google Chrome web browser just updated to the latest Version 66.0.3359.117 (Official Build) (64-Bit).
All I see is:
Once I enter my user credentials, the browser's screen goes blank.
Looks like this is the same issue as with Firefox.
Currently this expert mode command seems to help as a first workaround:
cp /web/htdocs2/js/login.js /web/htdocs2/js/login.js.orig; sed -i 's/if( form.isValid() ){/if( form.isValid() ){\nform.el.dom.action=formAction;/' /web/htdocs2/js/login.js
Note: This modification does not survive Jumbo Hotfix Updates.