Oh right I forgot about that.

Also back then (up until ~2005) browsers were hilariously insecure. For example I was in a forum of a local youth club and you could have signatures that were displayed under every post so I added some edgy image linked from my own webserver.

Some day I accidentally put the whole folder on a password protection which prompted the "username password" login window on every page my signature was linked to. FOR ALL USERS.

I realized users would think that the forum software would ask them to log in again for some reason so I basically got all passwords of people in the forum in plaintext on my webserver.

Crazy times

> reading the contents

Or having some javascript code in the page loaded by the iframe which could call some parent. function.

You could even do realtime stuff by leaving the HTTP socket open and writing out script tags when you needed to. https://en.wikipedia.org/wiki/Comet_(programming)

did you ping pong communicate data back and forth between iframe and "main frame" like a queue/pipe?

I also don't know how widespread this technique was back then, but I'm shocked this was left out of the article. This phenomenon was literally the method that transformed a "websites" into "webapps" in the early days. We would use pools of invisible iframes to constantly update different parts of the page for a "reactive" experience. The author mentions various important hacks that define the early days, but missing this one seems like a blunder to me.