[whatwg] Fwd: fallback section taking over for 4xx and 5xx responses while online

Josh Sharpe josh.m.sharpe at gmail.com
Thu Aug 23 21:12:22 PDT 2012

Cross posted to help at whatwg.org two days, but forwarding here since I think
this might be a problem with the spec/implementation.

As it stands now, I think the only way I see out of this pinch is to make
my 404 and 500 error pages return 200 response codes.


---------- Forwarded message ----------
From: Josh Sharpe <josh.m.sharpe at gmail.com>
Date: Wed, Aug 22, 2012 at 11:06 AM
Subject: fallback section taking over for 4xx and 5xx responses while online
To: help at lists.whatwg.org

I have a manifest that looks something like this:

# e4a75fb378cb627a0d51a80c1cc5684c2d918d93e267f5854a511aa3c8db5b1a


/ /offline

Notably, it has a "/ /online" fallback section which is, obviously, a
prefix for every page on my site.  This is good, because the goal is to
have my users redirected to what's at /offline when they navigate to
www.mydomain.com while offline.

As the fallback section is a prefix for everything, it's a prefix for any
url/path that results in an error condition such as a 404 or 500 response.
 Since there is an error, and the url matches, the fallback section is
triggered, displaying the contents of /offline and not the response from
the given URL.

It seems that the application cache, when it encounters an error state such
as a 404 or 500, doesn't check to see if the browser is still in the
'online' state, and immediately falls over to the fallback section.

While online, I would expect my 4xx and 5xx page to be rendered normally.

Finally, the fallback section in my example is very typical of most
examples I find in various docs, including the whatwg spec.  I don't think
I'm doing anything abnormal here.

Should I design this differently or is there something missing from the


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