[whatwg] scrdoc and session history don't play along in the spec

[Adam Barth]

On Sun, Jun 23, 2013 at 6:42 AM, Boris Zbarsky <bzbarsky at mit.edu> wrote:
> On 6/23/13 1:15 AM, Adam Barth wrote:
>> One tricky case here is what happens if you modify the srcdoc attribute:
>
> Ah, indeed.
>
>> <iframe id="foo" srcdoc="aaa"></iframe>
>>
>> <script>
>> [...] // Wait for the iframe to finish loading.
>> document.getElementById("foo").srcdoc = "bbb";
>> [...] // Wait for the iframe to finish loading.
>> document.getElementById("foo").contentWindow.document.body.innerHTML =
>> "ccc";
>> </script>
>>
>> What happens if you click the back button now?
>
> I believe Gecko's upcoming implementation will show "aaa", but I haven't
> tested to make sure.
>
>> That's because we navigated back
>> in the history to "about:srcdoc", which then looked at the srcdoc
>> property and saw "bbb" even though the srcdoc property had "aaa" when
>> that history entry was created.
>
> Ah, we're just storing the srcdoc text in the history entry for srcdoc
> loads, I think, precisely because you can't rely on the value of the
> attribute.

I guess it depends on what you mean by "rely".  We just treat the
about:srcdoc URL as something that, when fetched, retrieves the value
currently stored in the srcdoc attribute.  In this case, when you go
back, we'll fetch about:srcdoc again and get the current value of the
srcdoc attribute, "bbb".

Adam