[development] Weird Javascript behavior after form_set_error on Drupal forms

[Steven Jones]

David,

It's fairly standard practice to pop adding your js settings in a
simple function, and to use a simple static variable in that function
to ensure that the settings are only added once. Then you can then
call the function as many times as you want on a page load.

On Thursday, December 17, 2009, David Thibault <dthibault at esperion.com> wrote:
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> OK, this worked:
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> Add_js_css.inc (a file with all the Drupal_add_css and Drupal_add_js
> calls in it).
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> In hook_form_alter I did this:
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> If ($node->type == ‘purchase_order’) {
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>                 $form[‘#pre_render’][]
> = ‘load_js_css’;
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> }
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> In load_js_css() I did this:
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> require_once(‘add_js_css.inc.’);
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> return $form;
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> And that worked.
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> Thanks, Scott!
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> Dave
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> From:
> development-bounces at drupal.org [mailto:development-bounces at drupal.org] On
> Behalf Of David Thibault
> Sent: Thursday, December 17, 2009 1:41 PM
> To: development at drupal.org
> Subject: Re: [development] Weird Javascript behavior after
> form_set_error on Drupal forms
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> That almost works.  For some reason pre_render gets called
> twice and then it doubles up the calls to the Drupal_add_js (…settings)
> lines like this:
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> drupal_add_js(
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>     array('ldap_get_contact_details' =>
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>       array("json_url" =>
> $json_url)), 'setting');
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> My ajax calls use those settings to find the JSON urls to
> call.  If it gets called twice, then the settings array on the javascript
> side gets doubled up and breaks.  So then I moved those back to form alter
> (so they’d get called once) and left the other drupal_add_js and
> Drupal_add_css lines in the special my_load_js function.  Basically right
> now it’s stuck at putting them in form_alter and they don’t get
> called after the form_set_error returns, or put them in as pre_render options,
> and somehow that gets called twice in one page load.  I put a watchdog
> statement in my_load_js so that I could verify, and it does, in fact, get
> called twice per page load.
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> Thoughts?
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> Dave
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> From:
> development-bounces at drupal.org [mailto:development-bounces at drupal.org] On
> Behalf Of Scott Reynolds
> Sent: Thursday, December 17, 2009 1:14 PM
> To: development at drupal.org
> Subject: Re: [development] Weird Javascript behavior after
> form_set_error on Drupal forms
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> This is because on form error the form comes out of the
> cache table and skips fetching the form and all its _alter's. The
> 'best' practice I have found is to use a #pre_render function to
> drupal_add_js(). pre_render's are called always.
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> <?php
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> function my_form_alter() {
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>   // add my elements
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>   $form['#pre_render'][] = 'my_load_js';
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> }
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> ?>
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> <?php
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> function my_load_js($form) {
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>   drupal_add_js();
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>   return $form;
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> }
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> ?>
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> --
> Scott Reynolds
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-- 
Regards
Steven Jones
ComputerMinds ltd - Perfect Drupal Websites

Phone : 024 7666 7277
Mobile : 07702 131 576
Twitter : darthsteven
http://www.computerminds.co.uk