I’ve seen a lot of confusion about this lately, so I thought I’d make a quick writeup to explain how facebook does it. (I’ll also give a quick tip on how you can do it yourself.)

What Facebook Does

Facebook is in a unique position compared to many developers looking to set cross domain cookies: The user visits both facebook.com and the other website. (more…)

I’m working on a project that has a legitimate (non-spammy) reason to need cross-domain cookies, and we settled on flash as a good way to accomplish this.

However, I was surprisingly unable to find any complete library or how-to guide for connecting flash cookies to javascript. So I dusted off my flash skills and built one, and and now you get to enjoy the fruit of my labor:

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