You can’t delete more than one cookie at a time (and a couple other cookie bits)
Sometimes you glance at uncommented code and immediately know both what it’s trying to do (good!) and that it’s failing utterly to do it (bad!). Might be existing programmer slang for this, but I’m gonna dub it Error Code UTU8 (i.e. you thought you ate).
Like here in someone’s UTM tracking script:
document.cookie = "utm_campaign=, utm_medium__c=, utm_source__c=, utm_content__c=, utm_adgroup__c=, utm_keyword__c=; gclid__c=;expires=Thu, 01 Jan 1970 00:00:00 UTC;path=/;";
The code above is self-evidently trying to blank out a bunch of cookies that were set individually like so:
document.cookie = "utm_campaign=partner-invite-2024Q2;expires=Sat, 28 Dec 2024 12:34:56 UTC;path=/;";
document.cookie = "utm_medium_c=email;expires=Sat, 28 Dec 2024 12:34:56 UTC;path=/;";
document.cookie = "utm_source_c=blog-newsletter;expires=Sat, 28 Dec 2024 12:34:56 UTC;path=/;";
// etc.
Bad news for the developer: you must run the document.cookie setter separately for each cookie. There are no
