[html] What's the difference between IFrame and Frame?

Looking at options for embedding the 3D Secure page inside my own order form, I came across the following:

"Some commerce sites will devote the full browser page to the authentication rather than using a frame (not necessarily an iFrame, which is a less secure object anyway)."

from http://en.wikipedia.org/wiki/3-D_Secure

Can someone give me the lowdown as to why iframes are less secure, and cause problems, as opposed to normal frames? And what are the basic differences?

The way I see it, iframe is the way to go.

The only reasons I can think of are actually in the wiki article you referenced to mention a couple...

"The "Verified by Visa" system has drawn some criticism, since it is hard for users to differentiate between the legitimate Verified by Visa pop-up window or inline frame, and a fraudulent phishing site."

"as of 2008, most web browsers do not provide a simple way to check the security certificate for the contents of an iframe"

If you read the Criticism section in the article it details all the potential security flaws.

Otherwise the only difference is the fact that an IFrame is an inline frame and a Frame is part of a Frameset. Which means more layout problems than anything else!

Inline frame is just one "box" and you can place it anywhere on your site. Frames are a bunch of 'boxes' put together to make one site with many pages.

While the security is the same, it may be easier for fraudulent applications to dupe users using an iframe since they have more flexibility regarding where the frame is placed.

iframes are used a lot to include complete pages. When those pages are hosted on another domain you get problems with cross side scripting and stuff. There are ways to fix this.

Frames were used to divide your page into multiple parts (for example, a navigation menu on the left). Using them is no longer recommended.

IFrame is just an "internal frame". The reason why it can be considered less secure (than not using any kind of frame at all) is because you can include content that does not originate from your domain.

All this means is that you should trust whatever you include in an iFrame or a regular frame.

Frames and IFrames are equally secure (and insecure if you include content from an untrusted source).