339703 - Synchronous AJAX (SJAX) causes hang / lockup on error

Status: RESOLVED DUPLICATE of bug 190313

(Firefox :: General, defect)

Description

[Graham Leggett]

User-Agent:       Mozilla/5.0 (Macintosh; U; PPC Mac OS X Mach-O; en-US; rv:1.8.0.3) Gecko/20060426 Firefox/1.5.0.3
Build Identifier: Mozilla/5.0 (Macintosh; U; PPC Mac OS X Mach-O; en-US; rv:1.8.0.3) Gecko/20060426 Firefox/1.5.0.3

If an attempt is made to call a synchronous AJAX request like this:

RPCreq.open("POST", sURL, false);

and the server does not respond immediately, a complete lockup of Firefox follows.

What should happen is the tab in which the page is displayed should show synchronous behaviour (ie hang), but other tabs / the rest of the browser should remain functional.

(Note: This problem is widely reported on the net, but attempts to find this bug under the keywords "synchronous ajax" and "sjax" returned nothing.

There is widespread advice on the net to "not use synchronous ajax" and many good reasons are cited for not doing so unnecessarily, however when the application at hand specifically requires synchronous behaviour, synchronous ajax is the correct solution to the problem, and should be expected to work properly as it does in IE.

There are many extremely ugly workarounds to emulate SJAX using AJAX, which are infinitely worse than using ajax unnecessarily.)


Reproducible: Always

Steps to Reproduce:
xxx

Comment 1

[Rob Marshall [tH]]

*** This bug has been marked as a duplicate of 190313 ***