AHAH

AHAH Notes and Issues

Gotchas to watch out for

  • The callback must emit the JSON and nothing else. If it emits anything else, the JSON won't be parsed, and all will fail. How can it emit anything else, you ask? Well, if Devel module is turned on and it's timing pages and putting that at the bottom of the page, you're sunk. If Devel module is outputting errors to the screen, you're sunk. If you're debugging and you accidentally do a var_dump. nothing will work.
Topics: 
Drupal
AHAH

AHAH Example: Select control and generated checkboxes

Note that this is currently maintained in the Examples project so the code here may not be the latest.

In this example we use a select control to determine how many checkboxes are generated.

(Experience this one at http://d6.drupalexamples.info/examples/ahah_example/autocheckboxes.)

Topics: 
Drupal
AHAH

AHAH Resources

Topics: 
Drupal
AHAH

AHAH Example: Textfields driven by checkboxes

Note that this is currently maintained in the Examples project so the code here may not be the latest.

In this example, we just use checkboxes to determine whether textboxes are displayed.

One of the fundamental ideas of having a form change based on selections within the form is that the form is reconfiguring itself based on $form_state. So here, the generation of the form is driven by $form_state['values']. If the checkbox for last name is checked, then we generate a textfield for last name.

Topics: 
Drupal
AHAH

AHAH Changes for Drupal 7 (It's now called #AJAX)

Drupal 7 AHAH has changed its name to AJAX to use a more familiar term and to be slightly more trendy. A version of this presentation for D7 AJAX is at http://randyfay.com/ajax. D7 AJAX handling is massively simplified.

The AJAX Example for D7 is now in the Examples Module and will be maintained there. If you find AJAX features that you'd like to see in it that aren't there, file a request or submit a patch.

Topics: 
Drupal
AHAH
AJAX

Examples of AHAH in Drupal

  • Upload module (core) (Click a submit button and it adds another file)
  • Poll module (core) (Click a submit button and it adds another question)
  • Examples module (Drupal 6) provides a number of AHAH examples in the "AHAH Example module".
  • Quicktabs module (Configuration options change with the type of tab)
  • Amazon Store - Used in "add to cart" and selecting different product attributes.
Topics: 
Drupal
AHAH

AHAH Simplest Example: #ahah on the submit button, replace a region

Note that this is currently maintained in the Examples project so the code here may not be the latest.

The essence of AHAH is that you mark an element of a form as the one that activates AHAH behavior, and you tell it what section of the HTML is to be replaced when it's activated.

The form we're using here has a "markup" element, which is just plain HTML. It has a prefix and suffix that mention its CSS ID. The CSS ID will be used by the javascript running in the background to determine what's to be replaced.

Topics: 
AHAH
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