What are usability, accessibility, screen-reader or any other development, functionality, cross browser issue with iframe?

Question

What are the usability, accessibility, screen-reader, or any other development, functionality, or cross browser issues with <iframe>?

Is there any alternative for <iframe>?

And are there any JavaScript/jQuery or server-side techniques which can decrease the usability, accessibility, or screen-reader issues with <iframe>?

Why has the W3C not included <iframe> in XHTML Strict, while HTML 5 supports <iframe>?

update:

I found some good thoughts here also : http://uxexchange.com/questions/1817/iframe-accessibility-and-usability-issues

Answer 1

Accessibility:

• It's harder to scroll you iframe , your mouse must be int the range of the iframe. It difficult with people with movement desabilities
• Browsers for blind people may not include the content from you iframe and those people will not reach to it.

Usability:

• It's not cool when you have several scroll bars on the main window and on the iframe. It's difficult for scrolling

Other issues:

• Mobile browsers probably won't render you iframe. Even if it render it, it will look bad and ugly.
• Search engines will have hard time indexing your pages in the iframe. Probably they will skip it or won't take indexed properly
• Loading an iframe will take longer time than a page with the same content and no frame