[7530] in bugtraq
Re: Object tag crashes Internet Explorer 4.0
daemon@ATHENA.MIT.EDU (Paul Leach)
Wed Aug 5 13:18:12 1998
Date: Tue, 4 Aug 1998 14:42:41 -0700
Reply-To: Paul Leach <paulle@MICROSOFT.COM>
From: Paul Leach <paulle@MICROSOFT.COM>
X-To: "kragen@pobox.com" <kragen@pobox.com>
To: BUGTRAQ@NETSPACE.ORG
I meant the variant of HTML that includes object tags and J-Script/VB-Script
that has conditional statements and recursion -- which is enough to make it
Turing complete. If the precise name of that is DHTML, it's not relevant --
as far as users are concerened it's stuff in web pages that nearly all
browsers know how to and will execute and will throw it into a
non-terminating computation -- which makes it "HTML" as far as they are
concerned.
> -----Original Message-----
> From: kragen@pobox.com [mailto:kragen@pobox.com]
> Sent: Tuesday, August 04, 1998 2:37 PM
> To: Paul Leach
> Cc: BUGTRAQ@netspace.org
> Subject: Re: Object tag crashes Internet Explorer 4.0
>
>
> On Tue, 4 Aug 1998, Paul Leach wrote:
> > The possibility of infinite loops and infinite recursion in
> HTML has been
> > discussed on the lists before. Trying to detect and prevent
> them is an
> > instance of the "Turing machine halting" problem, and it is
> well known among
> > computer scientists to be impossible.
>
> Certainly not. HTML is not Turing-complete. In fact, detecting and
> preventing infinite loops and recursion in HTML simply requires
> traversing a directed acyclic graph and determining that it is, in
> fact, acyclic. This is simple.
>
> Perhaps you're thinking of DHTML. Or perhaps you're thinking of some
> kind of evil, twisted web server that serves up the same page under an
> infinite number of different names, each modified to include a frame
> reference to that page under a different name.
>
> Kragen
>
