Cancel synchronous xmlHttpRequest

[André Hänsel]

Hi,

when I perform a synchronous xmlHttpRequest by
my_xHR_obj.open('GET',url,false) I cannot abort this request by calling
my_xHR_obj.abort(). Furthermore any timeouts set by window.setTimeout are
not executed while the request is running. Scrolling the viewport also is
impossible.

I am a bit surprised because I think I tested this successfully a few weeks
ago. Maybe this is a regression in 3.5?

I am pretty sure that this is not the desired behaviour because of two
facts:

Firstly, on https://developer.mozilla.org/En/Using_XMLHttpRequest it is
written: "In versions of Firefox prior to Firefox 3, synchronous
XMLHttpRequest requests blocked the user interface. In order to make it
possible for the user to terminate frozen requests, Firefox 3 no longer does
so."

Secondly, on http://www.w3.org/TR/XMLHttpRequest/ in 4.2 an "ABORT_ERR
exception" is mentioned that "is raised when the user aborts a request in
synchronous requests". So how is it aborted?

Any ideas?

Regards,
André

[Jonas Sicking]

André Hänsel wrote:
> Hi,
>
> when I perform a synchronous xmlHttpRequest by
> my_xHR_obj.open('GET',url,false) I cannot abort this request by calling
> my_xHR_obj.abort(). Furthermore any timeouts set by window.setTimeout are
> not executed while the request is running. Scrolling the viewport also is
> impossible.
>
> I am a bit surprised because I think I tested this successfully a few weeks
> ago. Maybe this is a regression in 3.5?

Scrolling the viewport should be possible, if it's not please file a bug
and attach a testcase.

> I am pretty sure that this is not the desired behaviour because of two
> facts:
>
> Firstly, on https://developer.mozilla.org/En/Using_XMLHttpRequest it is
> written: "In versions of Firefox prior to Firefox 3, synchronous
> XMLHttpRequest requests blocked the user interface. In order to make it
> possible for the user to terminate frozen requests, Firefox 3 no longer does
> so."
>
> Secondly, on http://www.w3.org/TR/XMLHttpRequest/ in 4.2 an "ABORT_ERR
> exception" is mentioned that "is raised when the user aborts a request in
> synchronous requests". So how is it aborted?

Actually, the change in behavior was because people didn't *want*
timeouts to fire in the middle of sync XHR requests. No other browser
did it and pages were breaking over it.

/ Jonas