Setting cookie from a JavaScript file on another domain

Question

I have a site on domainA.com. It includes file.js from domainB.com:

<script type="text/javascript" src="http://www.domainB.com/file.js"&gt;&lt;/script&gt;

In file.js, I want to be able to set a cookie for domainA.com. How would I do this? It must be possible since Google Analytics does it for their __utma, etc. cookies.

Answer 1

I'm an idiot--apparently, this isn't actually a cross domain cookie and you can set it using document.cookie='blah'.