Why are WYSIWYG's always in iFrames?

Question

It seems like every WYSIWYG out there has an iFrame and that iFrames complicate the heck out of things. So why iframes?

Answer 1

Quoting MDC: "Rich-text editing is initialized by setting the designMode property of a document to "On", such as the document inside an iframe."

In other words, you can set a document inside an iframe to be editable, ie. enable user to write in it. It's not possible to do in inside a div (not with designMode at least).

You can, in theory, set div's content to be editable, but then you wouldn't be able to format it easily (which is an important feature of wysiwygs).

Read the MDC article for further details on how it's done.