HTML::Diff - compare two strings of HTML
This module compares two strings of HTML and returns a list of a chunks
which indicate the diff between the two input strings, where changes in
formatting are considered changes.
HTML::Diff does not strictly parse the HTML. Instead, it uses regular
expressions to make a decent effort at understanding the given HTML.
As a result, there are many valid HTML documents for which it will not
produce the correct answer. But there may be some invalid HTML
documents for which it gives you the answer you're looking for. Your
mileage may vary; test it on lots of inputs from your domain before
relying on it.
$result = html_word_diff($left_text, $right_text);
Returns a reference to a list of triples [<flag>, <left>, <right>].
Each triple represents a check of the input texts. The flag tells you
whether it represents a deletion, insertion, a modification, or an
Every character of each input text is accounted for by some triple in
the output. Specifically, Concatenating all the <left> members from the
return value should produce $left_text, and likewise the <right>
members concatenate together to produce $right_text.
The <flag> is either 'u', '+', '-', or 'c', indicating whether the two
chunks are the same, the $right_text contained this chunk and the left
chunk didn't, or vice versa, or the two chunks are simply different.
This follows the usage of Algorithm::Diff.
The difference is computed on a word-by-word basis, "breaking" on
visible words in the HTML text. If a tag only is changed, it will not
be returned as an independent chunk but will be shown as a change to
one of the neighboring words. For balanced tags, such as <b> </b>, it
is intended that a change to the tag will be treated as a change to all
words in between.
Whipped up by Ezra elias kilty Cooper, <email@example.com>.
Patch contributed by Adam <firstname.lastname@example.org>.