If a document is validated can it still cause a DOM program to crash?

The problem is that IMHO the DOM only offers one safe method to select elements: getElementsByTagName. This will always behave properly in a DWIM way. All the navigation functions, such as getFirstChid, getLastChild, getPreviousSibling and getNextSibling return a node. Now what if that node is a comment? How many of the DOM scripts out there check every time they use one of those methods that the result is really what they expected, usually an element? Remember that even if the DTD says that a dt is always followed by a dd there can be any number of comments and processing instructions in between. Who codes that defensively and systematically writes this?

my $dd= $dt;
$dd= $dt->getNextSibling until( $dd->getNodeName eq 'Element');

[download]

Hence my guess that a well placed comment can probably wreak havoc in most of the DOM code around (and certainly in most of my own tries at taming the DOM). Practically I suspect people code for a subset of XML, one that excludes comments and processing instructions. This is dangerous for the exact same reasons I described in On XML parsing.

In reply to Re: (fongsaiyuk)Re: Re: Which is the Best Perl XML Tool? by mirod
in thread Which is the Best Perl XML Tool? by sierrathedog04

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