Hi.
Can you clarify a bit? Is it that you want to use htmLawed with the Drupal software?
Some usage notes regarding htmLawed; pardon me if they are too simple or if you can already surmise them.
(1) The htmLawed code is invoked like any other PHP code. For example, one can have a PHP file named example.php with following code in a sub-directory of the PHP-enabled web-server's root directory
<?php
include('htmLawed.php'); // htmLawed.php is in the same directory as example.php
$text = '<em>Hello world!</em>';
echo htmLawed($text);
htmLawed will be invoked when the web-server is called to process example.php (e.g., when a web-site visitor browses to the web-address http://my.web-server.com/example.php).
(2) For Drupal, there is an htmLawed module. Using it involves downloading the module files, placing them at the right location in the Drupal file-system on the web-server, and then configuring htmLawed behavior using Drupal's web-based administrative interface. See https://drupal.org/node/255900.
(3) The htmLawed code cannot handle HTML code that is used in the <head> section of HTML documents. If a full HTML document, such as the entire text of a .html file, is passed to htmLawed, htmLawed will corrupt the document structure. So, htmLawed (just by itself) shouldn't be used to process entire HTML documents, such as the complete output of the Drupal content management system. htmLawed in the Drupal htmLawed module mentioned above only handles text that users type in the Drupal forms for comments, blog posts, etc. online. Such text after various filtering/processing gets displayed in the <body> (and not <head>) section of HTML documents that are created on the fly by Drupal.
(4) There is no need to alter the php.ini file on the web-server in order to use htmLawed. As long as PHP is enabled on the server, htmLawed will work when appropriately invoked through PHP scripts.
(5) It is theoretically possible to have every HTML document generated on a web-server (regardless of what generated them: Drupal, a Wiki software, static HTML files, etc.) filtered through htmLawed before being sent over the internet to a web-site visitor. However, I have not seen such an implementation.