296260 - Javascript include function call throws error when page is loading

Status: RESOLVED DUPLICATE of bug 252542

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

Description

[Matthew Schultz]

User-Agent:       Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.7.8) Gecko/20050511
Build Identifier: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.7.8) Gecko/20050511

When attempting to call a function from a javascript include file which was
listed before the function was called, an error is thrown in the console.  I've
tested this with the onmouseover event handler but I'm sure it's possible with
others.  It seems like the function is being called before the javascript file
is being included and as I understand it, nothing should be rendered on the page
before the javascript file is included.  

Reproducible: Sometimes

Steps to Reproduce:
1. Create a mouseover function in an include file
2. Include the file using a javascript include in an html page
3. Create an element with an onmouseover event handler in the html page 
4. Mouse over the element while the page is still loading

Actual Results:  
Throws an error in the javascript console even though the function is defined
before its called.

Expected Results:  
Don't throw an error in the javascript console.

The javascript file I am using to include is sending php server-side headers to
the browser to tell it not to cache.

Comment 1

[Matthew Schultz]

I took out the no-cache headers for the javascript include file and it still
throws errors, just not as often.  Still I am curious why the page is being
rendered before the javascript include functions are defined?

Comment 2

[Gervase Markham [:gerv]]

This is an automated message, with ID "auto-resolve01".

This bug has had no comments for a long time. Statistically, we have found that
bug reports that have not been confirmed by a second user after three months are
highly unlikely to be the source of a fix to the code.

While your input is very important to us, our resources are limited and so we
are asking for your help in focussing our efforts. If you can still reproduce
this problem in the latest version of the product (see below for how to obtain a
copy) or, for feature requests, if it's not present in the latest version and
you still believe we should implement it, please visit the URL of this bug
(given at the top of this mail) and add a comment to that effect, giving more
reproduction information if you have it.

If it is not a problem any longer, you need take no action. If this bug is not
changed in any way in the next two weeks, it will be automatically resolved.
Thank you for your help in this matter.

The latest beta releases can be obtained from:
Firefox:     http://www.mozilla.org/projects/firefox/
Thunderbird: http://www.mozilla.org/products/thunderbird/releases/1.5beta1.html
Seamonkey:   http://www.mozilla.org/projects/seamonkey/

Comment 3

[Matthew Schultz]

Auto resolve because no one has responded to this bug?  Lame.  Statistically
speaking, there aren't enough people to comb over the number of bug reports in
three months.  Can't spell focusing properly either?  This is still a bug
despite no one else commenting on it.  I just tested in build 20050908 (Firefox
1.5 Beta) and 20050910 (Seamonkey 1.0a).

Comment 4

[Yuh-Ruey Chen]

Well it would help if you could attach a testcase.

Comment 5

[Matthew Schultz]

Attachment: Script file to be included in testcase

Remote javascript file to be used with test case file.

Comment 6

[Matthew Schultz]

Attachment: Demonstrates javascript error on page load

This testcase demonstrates how mousing over/out input buttons which use the
onmouseover/onmouseout event handlers while the page is loading will cause
javascript errors.

Comment 7

[Matthew Schultz]

Attachment 198480 [details] apparently is more effective at demonstrating the bug on
bugzilla than my local computer possibly due to the fact that the connection to
the server is slower than loading the file locally.  

Comment 8

[Bob Clary [:bc] (inactive)]

I don't think this is JS engine, but it more probably parser. Blake, I can't reproduce this with a Firefox 1.0.x build nor in IE, but can in Firefox 1.5. Did we change external scripts to not block the parser?

Comment 9

[Blake Kaplan (:mrbkap) (inactive)]

No, we are correctly blocking the parser for this testcase. I wonder if the errors are coming from mousing over the previous page's event handlers after we've JS_ClearScope()d the old document and are in paint suppression for the new one.

I can't seem to reproduce this on the first page load, only on reload (i.e., when I've already loaded the page once, and it's currently on my screen). Is this the case for other people? If so, this might be related to bug 307777.

Comment 10

[Bob Clary [:bc] (inactive)]

(In reply to comment #9)

Good catch. First load... no errors mousing over. Reload... errors mousing over. And I was wrong in my earlier comment. 1.0.x has the same behavior. IE appears to deactivate the mouseovers on reload.

Over to DOM

Comment 11

[Erik Fabert]

*** This bug has been marked as a duplicate of 252542 ***