Per spec, the xpath is wrong. Given the following HTML:

<table>
  <tr>
    <td>Foo</td>
  </tr>
</table>

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The correct xpath to select the table cell is along the lines of //table/tbody/tr/td. Yes, there's an invisible <tbody> element in there! A standards-compliant HTML parser will always insert the <tbody> tag for you if you miss it out.

The /a/h3 part of the xpath is an interesting feature too. In HTML 4.x, <h3> is not a permitted child of <a>. What exactly to do when encountering such an element is undefined. Some parsers may close the <a> element early so that the <h3> ends up as a sibling of it rather than the child of it.

But under HTML 5 rules, <h3> is a permitted child of <a>. What does HTML::TreeBuilder do? Who knows!? HTML::TreeBuilder's documentation is pretty vague.

This is exactly the sort of reasons I maintain HTML::HTML5::Parser which is a fork of a third-party non-CPAN HTML5 parser, ported to run on top of XML::LibXML.

FWIW, this works for me...

use 5.010;
use PerlX::MethodCallWithBlock;
use Web::Magic -quotelike => 'web';

my @headings = web <http://docstore.mik.ua/orelly/perl4/cook/ch22_07.h
+tm>
    -> assert_success
    -> querySelectorAll("h3")
    -> map { $_->textContent };

say $headings[0];

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perl -E'sub Monkey::do{say$_,for@_,do{($monkey=[caller(0)]->[3])=~s{::}{ }and$monkey}}"Monkey say"->Monkey::do'

In reply to Re: can't extract node with HTML::TreeBuilder::XPath by tobyink
in thread can't extract node with HTML::TreeBuilder::XPath by saunderson

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