163437 - Disabled select does not automatically select an option

Status: RESOLVED FIXED

(Core :: Layout: Form Controls, defect, P3)

Description

[Martin Pecina]

User-Agent:       Mozilla/5.0 (Windows; U; WinNT4.0; en-US; rv:1.1b) Gecko/20020721
Build Identifier: Mozilla/5.0 (Windows; U; WinNT4.0; en-US; rv:1.1b) Gecko/20020721

When You can buy some goods, goods is not added to the shopping basket and JS
console shows this problem:

Error: uncaught exception: [Exception... "Index or size is negative or greater
than the allowed amount"  code: "1" nsresult: "0x80530001
(NS_ERROR_DOM_INDEX_SIZE_ERR)"  location: "http://www.tea.cz/cajovna/malobj.js
Line: 87"]

This JS problem has Mozilla from version 1.0+ Older version (0.9x-) works
normally without this error. Without this error works all Netscape browsers to
7.0 version too. 7.0+ version has the same problem. MS Explorer (4.0+) runs
without any JS error.

Reproducible: Always

Steps to Reproduce:
1.In the browser open http://www.tea.cz/cajovna/listobj.htm
2.Select some goods and click on the shopping basket icon
3.In the Shopping basket contents You will see nothing (JS error)
4.Open JS Console to see this error
Actual Results:  
In the Shopping basket contents You will see nothing (JS error)
Normal function (after Your fix) is that You will see added goods, description
and price.

Expected Results:  
Find this bug in the browser JS engine and fix it, please.

Error: uncaught exception: [Exception... "Index or size is negative or greater
than the allowed amount"  code: "1" nsresult: "0x80530001
(NS_ERROR_DOM_INDEX_SIZE_ERR)"  location: "http://www.tea.cz/cajovna/malobj.js
Line: 87"]

Comment 1

[Frederic Bezies]

Unable to connect to this URL.

Comment 2

[Phil Schwartau]

Martin: thank you for such a thorough report! The error you found,
NS_ERROR_DOM_INDEX_SIZE_ERR, shows this is either a coding error
at the site or a problem in the DOM. Reassigning to DOM component.

I would like to debug this, but like Frederic, I am unable to 
navigate to the site. I keep getting this error:

          www.tea.cz could not be found
          Please check the name and try again -

Is there a typo in the URL you gave? 

          http://www.tea.cz/cajovna/listobj.htm

Comment 3

[Jan Moesen]

Tried to connect to this URL from Belgium and from the Netherlands: both
attempts were unsuccessful. 

Is this the first case of a server being bugzilla-ed? (It just doesn't sound as
cool as ./-ed, though)

Comment 4

[Boris Zbarsky [:bzbarsky]]

The code in question is:

var hod = document.DCForm["x_" + i].options[document.DCForm["x_" +
i].selectedIndex].value;

Now as it happens, document.DCForm["x_" + i].selectedIndex is "-1" in this
case... so you get that error.

Comment 5

[Boris Zbarsky [:bzbarsky]]

Attachment: Minimal testcase

Martin, thank you for spotting the problem!  The issue is that a disabled
select does not automatically preselect its first option, unlike an enabled
select.  This is obvious in the display of the selects in this testcase and
clicking on the text should show the selectedIndex and the selected value,
which are -1 and exception in the case of the disabled select.	Note that
setting a chosen option as "selected" _will_ force the disabled select to
preselect it, so this could be a temporary workaround for the page if that's
needed.

Comment 6

[Boris Zbarsky [:bzbarsky]]

jkeiser, this is all yours.

Comment 7

[Boris Zbarsky [:bzbarsky]]

The issue is the following code in nsHTMLSelectElement::SelectSomething:

1755   // Don't select anything if we're disabled
1756   PRBool isDisabled = PR_FALSE;
1757   GetDisabled(&isDisabled);
1758   if (isDisabled) {
1759     return;
1760   }

I suspect we just want to remove it... depends on what IE does; NS4 does not
seem to support "disabled", so testing with it is pretty pointless.

Comment 8

[John Keiser (jkeiser)]

Attachment: Testcase (Disabled Options Too)

The difference is deliberate.  We don't ever select a disabled option unless
the page designer explicitly selects it themselves via an attribute or JS. 
It's unexpected behavior even if IE does it.  I don't think it's right to make
the disabled option "feature" the same as IE, and by inference it isn't right
to fix the disabled select problem.

The option that will be selected initially is deliberately not defined by the
spec, as well.

Comment 9

[John Keiser (jkeiser)]

OK, I relent.  It can be argued that a disabled *select* is different from a
select with disabled *options*; since a disabled select is not going to submit
you aren't doing anything strange by selecting options in it; you still don't
select disabled *options* in the disabled select, because if it were made
un-disabled you would end up submitting them.

Comment 10

[John Keiser (jkeiser)]

Attachment: Patch

Precisely as bz said it would be.

Comment 11

[Peter Lubczynski]

Comment on attachment 109506 [details] [diff] [review]
Patch

r=peterl

Comment 12

[John Keiser (jkeiser)]

Fix checked in.