On IE9 and Prototype 1.7, we're occasionally see this exception similar to 
this (the message is always the same):

UserAgent: 'Mozilla/5.0 (compatible; MSIE 9.0; Windows NT 6.1; WOW64; 
JSException: 'Could not complete the operation due to error c00c023f.'
JSUrl: 'https://XXXXXX/js/prototype.js?1310954924'
Timestamp: '{ts '2011-09-10 17:02:25'}' 

Our Prototype file is compressed using JSMin, but we've seen the same issue 
with uncompressed versions.  It appears that it's not just a Prototype issue 
since WebSync had a similar issue in their product -- here's the redux:

> It turns out this only happens if you've got the standards and IE9 
rendering modes both set (hence my inability to reproduce it at first - 
thank goodness for the dev tools in IE now), and you've got all script 
errors on, so the good news is that this won't be a problem for 99% of your 
users (unless they're running with script debugging on, which is *not* the 
default in IE9).

> For those who are interested in what the problem was: it shows up because 
an aborted request comes through with a readyState of "4", which is the same 
state as "successful", and we were processing it as such (intentionally - we 
check later for successful completion). However, in IE9, when you abort 
during an unload, the status, etc, doesn't get set properly, and when you 
try and read it an exception is thrown. We're now flagging requests in the 
unload event before they're aborted and ignoring them.


So it appears that Prototype isn't handling readyState "4" properly if the 
request is aborted.

Another reference is here:


Are others seeing this issue...?? And what needs to be done to get this 

You received this message because you are subscribed to the Google Groups 
"Prototype & script.aculo.us" group.
To view this discussion on the web visit 
To post to this group, send email to prototype-scriptaculous@googlegroups.com.
To unsubscribe from this group, send email to 
For more options, visit this group at 

Reply via email to