Another obscure WordPress problem: setting document.domain for cross-site scripting iframes breaks Gravity Forms AJAX submissions

Whew… that title was almost as long as the variable name I’m about to throw out in a code example.

I spent well over an hour beating my head against the wall on this problem today before narrowing it down to a Gravity Forms issue. The scenario: I have a site that is loading iframes from a different subdomain. As is common in this situation, I wanted to be able to adjust the height of the iframe with JavaScript, to match the height of the page within the iframe and prevent internal scrollbars.

The solution to that problem is readily available on teh interwebz, with the addition of a bit of extra JavaScript to allow cross-site scripting: both the containing page and the contained page need to specify the same document.domain so browsers will let them talk to each other.

Not long after we put this in place, my client informed me that none of their AJAX-based Gravity Forms were working. The spinner would just spin indefinitely, even if (usually) the form actually did submit properly. It didn’t take me long to narrow the problem down to a JavaScript error pertaining to cross-site scripting. I found that AJAX and document.domain don’t mix. Or at least that seemed to be the issue.

But that’s where I hit a wall. No one else seemed to be describing the exact problem I was having. Most solutions involved adding a Access-Control-Allow-Origin header, but that didn’t do anything for me.

Eventually I realized that was because the problem wasn’t with the AJAX, per se. It was the fact that Gravity Forms adds its own hidden iframe where it works some secret mojo on AJAX submissions. And that iframe needed to have document.domain added to it, just like my site and the other subdomain I was loading in iframes did.

So the question then was, is there a Gravity Forms hook to modify its iframe output? Fortunately, the answer is yes.

The gform_ajax_iframe_content filter pretty much does what it says on the tin. Add a filter to insert the necessary JavaScript, and you’re good. The only thing I don’t get about this is the name given to its lone input parameter. I mean, really? (Actually… I do think I understand it, but I don’t understand it.)

Anyway… here’s what you need to make this work. Just replace with the correct domain name. And if you’re running on a version of PHP before 5.3, you won’t be able to use an anonymous function. But you’re not running an old version of PHP, are you?

add_filter('gform_ajax_iframe_content', function($doctype_html_html_head_meta_charset_utf_8_head_body_class_gf_ajax_postback_form_string_body_html) {
  echo "<script>document.domain = '';</script>\n";
  return $doctype_html_html_head_meta_charset_utf_8_head_body_class_gf_ajax_postback_form_string_body_html;

Make Advanced Custom Fields smarter about handling date fields

I love Advanced Custom Fields almost as much as I love WordPress itself. But that’s not to say it doesn’t have its problems. Most are obscure, and minor… and incredibly aggravating once you stumble upon them.

Here’s one such case. Date Picker fields are great, but no one seems to be able to agree on how to store dates in a database… other than insisting on avoiding Unix timestamps, the obvious choice.

ACF stores its dates, for some reason, in YYYYMMDD format (or, as we’d express it in PHP Land, Ymd). No delimiters at all. If you’re not going to use Unix timestamps, why not at least use the MySQL convention of Y-m-d H:i:s? But I digress.

I’m presently working on a project that merges some functionality of ACF and Gravity Forms, along with some custom code, to create a jobs board. It’s super-slick how Gravity Forms can create posts from a form submission, and even set them to pending review so a site editor can come in and review them before publishing.

But… dates. Jobs boards have a lot of dates. And while Gravity Forms offers a wealth of options for date string format, Ymd isn’t one of them. So it ends up storing the date value in the database in a format ACF doesn’t like. Because ACF is very picky. It wants that format, and no other. If the value in the field is not in Ymd format, the value displayed on the admin editing screen is just… blank. And then when you save, whatever was previously saved in that field is erased.

It doesn’t have to be this way. And thanks to the following bit of code, it won’t be. Now bear in mind, this is only altering what ACF renders on the editing screen. Once you’ve saved again from that point, the date will be stored in ACF’s preferred format, but up until then, it will be in whatever other format it was in when it landed in the database.

If you’re writing your front end code proactively, that won’t matter. Because you’re already assuming data inconsistency and using strtotime() to standardize any dates you’re working with in your templates, right? Of course you are.

OK, then. So the real goal here is just to get ACF to display the correct, saved date when you go in to edit the post, so it doesn’t then wipe out the date when you hit Save Changes.

In your functions.php file, or wherever you think is best (a plugin would be nice), do this:

function acf_smart_dates($field) {
  if ($field['value']) {
    $field['value'] = date('Ymd',strtotime($field['value']));
  return $field;

That’ll do.