Hidden Metadata Fields can be used to capture metadata about the form submission, such as the URL referrer or supporter’s affiliate ID. These inputs do not display on the supporter-facing form.
Creating Hidden Metadata Fields
You can create Hidden Metadata Fields in Online Actions on the Settings tab. There, you can define the Identifier, Display Name, and Description. Note that the Identifier is an alphanumeric value that always starts with “oa_”, cannot contain any spaces, and is case-insensitive.
Once created, the hidden input is available on every form without the need to republish.
Populating Hidden Metadata Fields
There are two ways to populate Hidden Metadata Fields: query strings and JavaScript.
A query string is ideal when the same value should be applied to all supporters coming from the same link, such as from an email or ad. To populate a Hidden Metadata Field using a query string, use the Identifier as the “name” portion of the name-value pair. Example: ?oa_email_send_date=2021-02-02
JavaScript allows you to add your own logic to collect information about a supporter’s browser session and is a better fit when an Identifier’s value is likely to be different from one supporter to the next. To populate a Hidden Metadata Field using JavaScript, we recommend using ActionTag’s alterPost callback to populate that field’s Identifier. View this alterPost callback example to populate an oa_visitor_id Hidden Metadata Field.