Text::Diff::HTML - XHTML format for Text::Diff::Unified


    use Text::Diff;

    my $diff = diff "file1.txt", "file2.txt", { STYLE => 'Text::Diff::HTML' };
    my $diff = diff \$string1,   \$string2,   { STYLE => 'Text::Diff::HTML' };
    my $diff = diff \*FH1,       \*FH2,       { STYLE => 'Text::Diff::HTML' };
    my $diff = diff \&reader1,   \&reader2,   { STYLE => 'Text::Diff::HTML' };
    my $diff = diff \@records1,  \@records2,  { STYLE => 'Text::Diff::HTML' };
    my $diff = diff \@records1,  "file.txt",  { STYLE => 'Text::Diff::HTML' };


This class subclasses Text::Diff::Unified, a formatting class provided by the Text::Diff module, to add XHTML markup to the unified diff format. For details on the interface of the diff() function, see the Text::Diff documentation.

In the XHTML formatted by this module, the contents of the diff returned by diff() are wrapped in a <div> element, as is each hunk of the diff. Within each hunk, all content is properly HTML encoded using HTML::Entities, and the various sections of the diff are marked up with the appropriate XHTML elements. The elements used are as follows:

  • <div class="file">

    This element contains the entire contents of the diff "file" returned by diff(). All of the following elements are subsumed by this one.

    • <span class="fileheader">

      The header section for the files being diffed, usually something like:

        --- in.txt    Thu Sep  1 12:51:03 2005
        +++ out.txt   Thu Sep  1 12:52:12 2005

      This element immediately follows the opening "file" <div> element.

    • <div class="hunk">

      This element contains a single diff "hunk". Each hunk may contain the following elements:

      • <span class="hunkheader">

        Header for a diff hunk. The hunk header is usually something like:

          @@ -1,5 +1,7 @@

        This element immediately follows the opening "hunk" <div> element.

      • <span class="ctx">

        Context around the important part of a diff hunk. These are contents that have not changed between the files being diffed.

      • <ins>

        Inserted content, each line starting with +.

      • <del>

        Deleted content, each line starting with -.

      • <span class="hunkfooter">

        The footer section of a hunk; contains no contents.

    • <span class="filefooter">

      The footer section of a file; contains no contents.

You may do whatever you like with these elements and classes; I highly recommend that you style them using CSS. You'll find an example CSS file in the eg directory in the Text-Diff-HTML distribution. You will also likely want to wrap the output of your diff in its own element (a <div> will do) styled with "white-space: pre".

See Also



This module is stored in an open GitHub repository. Feel free to fork and contribute!

Please file bug reports via GitHub Issues or by sending mail to


David E. Wheeler <>

Currently maintained by the developers of The Perl Shop <>.

Copyright and License

Copyright (c) 2005-2011 David E. Wheeler. Some Rights Reserved.

This module is free software; you can redistribute it and/or modify it under the same terms as Perl itself.