Remove unwanted form elements (example: removing Your name: <username> from comment forms)

These code snippets illustrate how to unset (remove) any undesired form element from a specific form. If you don't want to only remove elements from a form, you can also alter existing values or add new elements to a form using these methods. The example in this lesson uses the Comment form, removing the Your name: <username> (which appears only to logged in users) as well as the title above the textarea of the form. There are two ways you can accomplish this, either using hook_theme() in your template.php, or using hook_form_alter() in a custom module. Both methods are very useful, and you will learn a lot by attempting both.

Using hook_theme() in template.php

Instead of this lesson repeating already existing (and excellent) information, instead please see Using hook_theme() to modify forms and Lullabot: modifying forms. Below is the code for this particular example. Add the following code snippet to your template.php file. Replace MYTHEME with the name of your own theme (e.g. garland) and clear the theme registry after adding the code (see Administer > Site configuration > Performance). Do not include the opening and closing php tags.

Using hook_form_alter() in a custom module

Many Drupal developers/themers create a small "personal" module to paste or add various bits of code into which have to be applied from a module rather than within the theme template files (some things cannot be modified from the theme layer, while they can be modified from within a module). It's useful to name the module customsite or something along those lines (rather than a site-specific name), as you can then easily recycle the code for future Drupal sites without needing to adjust anything.

If you do not yet have a personal module, you should create one now following the steps below. If you do have a Custom module, simply paste in the function from the code below for altering the form, and you're done.

First make a folder at sites/all/modules/customsite which is where you will save the following two files.

Make a file called customsite.info and paste in the following code:

Make a file called customsite.module and paste in the following code:

In the above code the "Comment:*" title that usually shows directly above the main textarea of the form was also removed using the second unset line (since the text "Post new comment" or "Reply" already shows above the form, removing this extra title helps simplify the form (the textarea does not really need a title: its purpose is already self-evident without the additional text).

After saving these two files, go to Administer > Site building > Modules (admin/build/modules) and enable the new "Custom Site functions" module that you've created. Go view a comment form to ensure that it worked as expected.

You can identify other forms throughout the site and alter them in a similar fashion. Viewing the source of the rendered page in your browser will often reveal the form ID with which you can locate the code in a module that is generating the form. Search the module's code for that ID and it should bring you directly to (or at least close to) the part of the code you wish to alter. More tips on finding the form ID are available in Lullabot's Modifying forms article.

The "Changing Forms with hook_form_alter()" pages of the Pro Drupal Development book are also very helpful in learning more about altering forms.