The <iframe>
is not deprecated at all. At least, the current HTML5 spec draft on <iframe>
doesn't say anything about deprecation. In the future please read the specification itself before making ungrounded assumptions.
There's however an alternative to the <iframe>
which allows graceful degradation: the <object>
tag which in the below example gracefully degrades to a link when the specified content type is not supported by the browser nor any of its plugins (you know, displaying a PDF file inline requires the Acrobat Reader plugin).
<object data="/url/to/file.pdf" type="application/pdf" width="500" height="300">
<a href="/url/to/file.pdf">Download file.pdf</a>
</object>