libhtml-tidy-perl software package provides module for (X)HTML validation, you can install in your Ubuntu 14.04 LTS (Trusty Tahr) by running the commands given below on the terminal,
$ sudo apt-get update $ sudo apt-get install libhtml-tidy-perl
libhtml-tidy-perl is installed in your system.
Make ensure the libhtml-tidy-perl package were installed using the commands given below,
$ sudo dpkg-query -l | grep libhtml-tidy-perl *
You will get with libhtml-tidy-perl package name, version, architecture and description in a table
| Distro | Ubuntu 14 04 lts trusty tahr |
| Section | Perl |
| Package | libhtml-tidy-perl |
| Version | 1.56-1 |
| Description | module for (X)HTML validation |
| Sub Section | Perl |