? kills IE Mac

[Jeff Thies]

I have a script with a regex

var re = /\/(\w+?)\//;

In IE5 Mac, that kills all javascript, anywhere on the page. No errors
but no functionality at all. Just the mere presence of that line without
it being called.

removing the "?", returns everything normal.

var re = /\/(\w+)\//;

Why could that be?

Is the default regex behaviour non greedy and the "?" really uneeded?

Cheers,
Jeff

[Michael Winter]

Re: ? kills IE Mac

On Sat, 25 Dec 2004 00:07:22 GMT, Jeff Thies <jeff@spamalana dingong.com>
wrote:
[color=blue]
> I have a script with a regex
>
> var re = /\/(\w+?)\//;
>
> In IE5 Mac, that kills all javascript, anywhere on the page.[/color]

As I understand it, versions of IE prior to 6 don't support non-greedy
matching. Microsoft's documentation isn't specific about this and I don't
have access to earlier versions, so I could be wrong.

[snip]
[color=blue]
> Is the default regex behaviour non greedy and the "?" really uneeded?[/color]

The default is greedy matching, but it doesn't matter here. The two
slashes can't be matched as part of the \w character class.

Mike

--
Michael Winter
Replace ".invalid" with ".uk" to reply by e-mail.

[Martin Honnen]

Re: ? kills IE Mac



Jeff Thies wrote:
[color=blue]
> I have a script with a regex
>
> var re = /\/(\w+?)\//;
>
> In IE5 Mac, that kills all javascript, anywhere on the page. No errors
> but no functionality at all. Just the mere presence of that line without
> it being called.
>
> removing the "?", returns everything normal.[/color]
[color=blue]
> Why could that be?[/color]

Browsers implemented regular expressions in JavaScript before the
ECMAScript edition 3 standardized them so in browsers like Netscape 4 or
IE 5/Mac or IE 5/Windows (in the standard installation, on Windows it is
possible to update the JScript engine without changin the IE version)
you find regular expression support but not with all the features
standardized in ECMAScript edition 3. The non-greedy matching with '?'
placed after a quantifier is one of the features that those older
browsers do not support so IE 5/Mac probably chokes on that regular
expression syntax and that way stops executing the script. That it kills
all JavaScript sounds unlikely, if there are several <script> blocks in
a page an error in one should not kill execution of the other script
blocks. But I am not too familiar with IE 5 on the Mac.

--

Martin Honnen

http://JavaScript.FAQTs.com/