hook_form_alter

On one Drupal site I'm developing, there is an 'embed code generator' in one of the site's forms. This embed code capability is similar to Twitter's embeddable timeline widget, in that a user can select some parameters (colors, mostly), then some code (usually an iframe with the contents provided by an external site) is printed in a textarea, which the user can select, and paste into his own site's HTML.

To help the user in the task of selecting the code, the entire contents of the textarea or textfield is highlighted when the user clicks any part, which ensures that the user will get every last bit of code without having to select and drag his mouse around the text box (sometimes I've seen people missing part of a tag, which makes the embed fail to load). That's what we want to do, inside our own Drupal form.

First, in the drupal form itself (or via an hook_form_alter()), we need to attach a javascript file in our custom module (in this example, I assume you have a module called custom.module, and a js file named 'custom.select-helper.js' in your custom module's directory, inside a 'js' folder):

With the awesome new #states implementation in Drupal 7, and for form usability in general, it's often good to be able to selectively, or completely, disable form autocompletion for your users. One example I just encountered was a form that has two fields that are alternatively shown or hidden depending on the value of a checkbox earlier in the form. However, Google Chrome, in its infinite wisdom, was autofilling the hidden field, which shouldn't have a value if hidden, so I had to set the input's 'autocomplete' value to 'off.'

For simple textfields, here's how you could do that in a hook_form_alter() (in this example, I was disabling autocomplete on the user registration form's email field):

...or, "Always Check Your Module Weights when form_alter'ing"

I spent about half an hour today trying to use hook_form_alter() to move the 'Scheduling options' fieldset (provided by the Scheduler module) out of my node form's vertical tabs (down where URL path settings, comment settings, etc. are jumbled together).

I couldn't even see the 'scheduler_settings' form settings when I looked at the form's array, even though I knew it existed (since it was being displayed, and the scheduler.module defined it using its own hook_form_alter().