207271 - Exception when trying to access property in not yet completely loaded frame

Status: RESOLVED INVALID

(Core :: DOM: Core & HTML, defect)

Description

[Daniel]

User-Agent:       Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; .NET CLR 1.0.3705)
Build Identifier: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.4b) Gecko/20030507

By accessing a property in a chat output frame which is never 100% loaded I 
get "Error: uncaught exception: Permission denied to get property 
Window.check". Property Window.check is a variable declared in this chat 
output frame: var check = true;
Accessing it by calling alert(parent.chatoutput.check) or just trying to get 
it's type (typeof parent.chatoutput.check) results in an exception. Maybe 
there is another reason for this happening but I am reporting this bug because 
IE (maybe it is not worth to refer to it in this case) is able to handle this 
correctly and I am very sure that there cannot be another reason for it 
because I checked the Java Script Console and there are no more errors than 
this one.

Reproducible: Always

Steps to Reproduce:
1. Creating two frames of which one is always loading.
2. Accessing a property of the second frame (it happens in both cases).
3. Described exception will appear.

Actual Results:  
An exception is displayed:
Error: uncaught exception: Permission denied to get property Window.check

Expected Results:  
Return an "undefined" type and/or value if the frame is not present or return 
the value of the property.

Comment 1

[Phil Schwartau]

Browser, not engine. Reassigning to DOM Level 0; cc'ing Mitch -

Comment 2

[Daniel]

I have to correct myself. This bug does not depend on the still loading frame, 
it depends on using the same host but a different port. Mozilla restricts 
access to frames which are not the same host. I am using "localhost:80" (Web) 
and "localhost:1983" (Chat Output) so that Mozilla denies permission because 
of the different port but same host. I think this should be changed in advance 
to developers of software of this kind. IE supports same host but different 
ports in this case. Currently I am using a workaround by having the chatserver 
serving the second frame - but so the server lags a litle bit :/. Maybe it is 
not really necessary to restrict access to different ports.

Comment 3

[Phil Schwartau]

Daniel: perhaps you would be interested in Security bug 163410,
"Security Error: Content at http://{xxx} may not load data from {yyy}."

That sounds similar to the issue you're describing. Perhaps we should
even reopen this bug and assign it to Security for an opinion.

Thoughts?