[development] Drupal way of doing onchange

[Earl Miles]

Jeff Greenberg wrote:
> Haven't delved into AHAH yet, this might force the issue.
>
>
> Using an easy (=less typing) example. A credit card form. When the 
> credit card type is selected from a select, the selection needs to 
> fire a javascript function that will disable fields that don't apply 
> to that card type (such as CVV).
>
>
> Normally, I would have an onchange event for the select, and noticed 
> that in the form api, while there is an attribute section to add 
> miscellaneous attributes, the doc doesn't mention events as examples. 
> And if putting an event there is legitimate, there isn't a mention of 
> how to include the responding js function in the form.
>
>
> If AHAH is the way I'm supposed to handle this, I'd appreciate being 
> pointed to a good similar example, because I'm a bit unclear from the 
> AHAH entries in the form reference docs, for example, how to relate 
> the myhandler/js entry to a physical location of the function, and how 
> the function gets there.
>

You wouldn't use AHAH. CTools as a tool called 'dependent' that will 
help you do this kind of behavior without having to write any javascript.