Question

How can I make the browser insert <p> tags instead of <br> tags when I press enter in a designMode IFrame? I get inconsistent behavior across Firefox, Chrome and IE and was wondering if there was some way to normalize this.

Answer 1

It seems you can’t. Behaviour is not standardized and control for this is rudimentary at best

This is an interesting thread from May thie year on the matter: http://lists.whatwg.org/htdig.cgi/whatwg-whatwg.org/2011-May/031577.html . It’s discussing contenteditable rather than designMode but they’re effectively very similar.

An email on the thread ( http://lists.whatwg.org/htdig.cgi/whatwg-whatwg.org/2011-May/031604.html ) from Simon Pieters (zcorpan) of Opera says:

Opera 11.10 has introduced
document.execCommand(‘opera-defaultblock’,”,’div’) to switch to using
<div>s instead of <p>s. (‘p’ is also allowed to switch back.) Apparently
WebKit considers implementing this as well.
https://bugs.webkit.org/show_bug.cgi?id=59961

Further in the thread there’s also this email http://lists.whatwg.org/htdig.cgi/whatwg-whatwg.org/2011-May/031685.html by Markus Ernst including this comment:

I assume there are use cases for both generating <p>s and <br>s. The
IE/Opera approach has the advantage of allowing both, which is perfect
for text and basic HTML editing. From a WYSIWYG POV it might be best
to offer both options, so authors are not encouraged to add
server-side processing to change the output, which would break
WYSIWYG.

If the behavior is settable, it might even be a good idea to leave the
choice of the standard behavior to the UAs. Authors who have a reason
to care can set their preferred behavior, while other authors might
prefer to leave it as it was, so there is no change for their
existing users.

There’s lots more on the thread about what people at the various browser makers think ought to happen, comments on some very strange existing behaviours, and general discussion about the problem involved in implementing it at all.

The currently very alpha spec for all this is at http://aryeh.name/spec/editing/editing.html