More string indexing semantics issues

Maciej Stachowiak mjs at
Wed Jun 25 18:36:59 PDT 2008

On Jun 25, 2008, at 2:33 PM, Garrett Smith wrote:

> On Wed, Jun 25, 2008 at 1:52 PM, Maciej Stachowiak <mjs at>  
> wrote:
>> I have not seen any reports of such problems. If it were common to  
>> put
>> random numeric properties on String objects, I expect we would have  
>> had a
>> bug report by now.
> Why?

What I meant is this:

1) When Safari/WebKit/JavaScriptCore diverges from other browsers in  
JavaScript behavior, in ways that Web content depends on, we have  
historically gotten bug reports even when the issue is very obscure.  
See my earlier comments about things like function declarations in  
statement position for examples.

2) We have not gotten bug reports that involve a site breaking because  
it set a low numeric property on a String object, and did not get the  
expected value back. At least, none have been found to have this as  
the cause. In other words, we have not seen cases like this:

var s = new String("abc");
s[0] = "expected";
if (s[0] != "expected")
     alert("EPIC FAIL");

3) Therefore, I think it is unlikely that a lot of public Web content  
depends on being able to do this. If this were at all common, odds are  
that we would have heard about it by now. As Brendan suggests,  
deploying the behavior in beta versions of other browsers would give  
us more data points.

> Do you are there many Webkit only applications? Do these
> applications take advantage of string indexing via property access?

I do not think the existence of WebKit-only applications is relevant.  
There are in fact a fair number (for example Dashboard widgets and  
iPhone-specific Web apps), but they do not tell us anything about  
whether public Web content at large depends on the behavior of  
allowing any numeric property of a String object to be successfully  
assigned. (I do not think any of this content depends on the WebKit  
behavior either).


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