(TUTORIAL) Overriding contact.module, no core hacking required! : www.trevortwining.com

Learn how to hack Default Contact Module in Drupal.

 " Wow, this was a really tough one. I learned how to totally redesign the Drupal contact form without hacking a single line of core.

Here's what we needed.

First, it will help to tell you that I put this code in a custom client-specific module. I use this approach when developing client sites. I create a module with the client name and then put any customizations that are needed to forms, theme functions, etc. inside of it. It helps keep things better maintaned. If enough customizations are needed, I suppose I would then put each grouping into its own module, and keep them within the same module category. "

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http://www.trevortwining.com/content/overriding-contactmodule-no-core-hacking-required