Question about IFrame

I had been going through Iframe related questions and got stuck with this.

They break the one-document-per-URL paradigm, which is essential for the proper functioning of the web (think bookmarks, deep-links, search engines, ...).

Moreover, if I ask开发者_开发问答 you to tell me the difference between Iframes and Frames, what is the easiest way to explain it?

Frame allows you to display multiple documents on page.

They all have distinct URLs which are hidden from you. So, you cannot bookmark them separately.

An iframe is a frame in an otherwise normal document.

Normal frames are placed in a document which consists entirely of frames (plus, hopefully, some fallback content from user agents that don't support them).