86166 - <script language="Javascript1.2"> causes incompatible result format of Array.prototype.toString()

Status: VERIFIED WONTFIX

(Core :: JavaScript Engine, defect)

Description

[Stephan Tolksdorf]

When a script is included with language="JavaScript1.2" Mozilla 
Array.prototype.toString's behaviour is incompatible to the one of IE, 
Navigator 4 and to what ECMA says.

Sample code:
var s = "string";
var a = [s];
alert(a);
//IE and Navigator 4 show 'string' (without the outer quotation marks)
//Mozilla shows '["string"]'
//ECMA: toString() has to be the same as join()

A more elaborate example is attached.

Comment 1

[Stephan Tolksdorf]

Attachment: Script that shows incompatible behaviour

Comment 2

[Phil Schwartau]

When you do "alert(a)", you are implicitly doing a.toString().

In JS 1.2,  Array.toString()  functioned like  Array.toSource() does now: 
that is, it gave something you could recompile back into the array.  
This is specific to version 1.2.

Comment 3

[Stephan Tolksdorf]

Apparently this is specific to JavaScript 1.2 as it is implemented in Mozilla. 

But why should Array.toString() function in JS 1.2 like Array.toSource()?
In IE4+, Nav4+ and even Navigator3 Array.toString() is implemented to function 
like Array.join().

Comment 4

[Phil Schwartau]

> But why should Array.toString() function in JS 1.2 like Array.toSource()?

This was a decision made at Netscape years ago. There are at least 
two major implementations of JavaScript: one by Netscape (where JavaScript 
was created, by Brendan Eich) and one by Microsoft. The two implementaions 
differ from each other in slight ways. 

The ECMA standard has also changed over time. What the standard says now
is not necessarily what it said at the time JS1.2 was being developed.

In the Netscape implementation, version 1.2 of the language differs 
in some noticeable ways from all other Netscape versions, and you have 
discovered one of these ways. 

I will attach an HTML testcase that shows another technical difference
between Netscape JS1.2 and all other Netscape versions (and IE JS1.2).
You can try this testcase in IE, NN4.x, and Mozilla/N6.

Comment 5

[Phil Schwartau]

Attachment: HTML Netscape-JavaScript 1.2 detector

Comment 6

[Phil Schwartau]

You raise an interesting question: why does Mozilla behave differently
on your testcase than NN4.7? It is understandable if IE behaves 
differently, because Microsoft JavaScript 1.2 is not identical to 
Netcape JavaScript 1.2. But why should NN4.7 and Mozilla behave 
differently? This is a good question!

I will attach a reduced version of your testcase below with the 
<style> and <div> tags removed. Only the JavaScript remains. 
Now we see NO difference between NN4.7 and Mozilla!!!

                  NN4.7   shows '["string"]'
                  Mozilla shows '["string"]'

Comment 7

[Phil Schwartau]

Attachment: Reduced version of Stephan's testcase: no <style> or <div>

Comment 8

[Phil Schwartau]

Stephan, thank you for this report! 

But I have to mark this bug as WONTFIX. The behavior of JS1.2 was decided 
at Netscape (and Microsoft) years ago. Many web pages have been written 
since that time with <script language="Javascript1.2">. We cannot change 
Netscape JS1.2 now without breaking web pages that rely on its behavior.

Any new web page that does not need to use the features of a particular
version of JavaScript should always use <script language="Javascript">.

Comment 9

[Phil Schwartau]

Marking Verified.

Note: the bug with NN4.x on your testcase is real, in my opinion. 
But bugs against NN4.x are not for Bugzilla. Here is a URL for that:

          http://help.netscape.com/forms/bug-client.html


Again, thank you for helping us. It is contributors like you who
catch the things we miss -