Long story short, I was developing a Facebook page application which runs from inside a page tab. Such applications runs inside an iframe on Facebook Fanpage. Everything was going perfectly, until, we started checking it in IE!! The symptoms were simple, PHP Session is not working when user logs in. The application works perfectly in Safari, Opera, Chrome and Firefox and only the Elite of the Elites Internet Explorer is not accepting any cookie generated from the application.

I was hungry, almost lunch time – client was kicking my ass, so I couldn’t even think to grab a bite. I was VERY HUNGRY, clueless, lost and I was feeling like yelling at everything that walks in front of me. Oh boy, I was absolutely clueless about what was done wrong to satisfy this King Blue E.

After discussing my problem with Uncle G for over 5 hours, trial and error, do this and that, I realized that the problem is actually related to p3p privacy policy and how Internet Explorer deals with it. It doesn’t accept any cookie from any web application which is running inside an iframe within another application. Let me clarify

1. Web application A with domain a.com has an iFrame in one of its page
2. Inside that iFrame, it loads another web application B with domain b.com
3. Now Internet Explorer doesnt accept any cookie which generates by Web Application B, resulting a catastrophe, a real disaster.

The Solution: send the following header in your web application which runs inside the iFrame.

[sourcecode language=”php”]
<?php
header(‘P3P: CP="CAO PSA OUR"’);
header(‘P3P: CP="HONK"’);
?>
[/sourcecode]

and it fixes this weird behavior of Internet Explorer. Freaking p3p! wastage of 6 hours, remaining hungry, missing lunch, get kicked on the ass and what not.

I hate you Internet Explorer. You are the worst thing ever made in the history of web development. I sincerely hate you. And Microsoft, with all the Blue E fan-boys out there, GO TO HELL and let us live our life.

Morons!