Search Add-on: Adding additional fields to the search form
The Search Add-on supports adding additional fields to the search form. These fields are created by adding a custom code snippet in your theme’s functions.php file.
Example #1 – filter by meta values
You can create a new field that filters calendars based on a custom meta values from the post assigned to the calendar. You can use the $data[‘post_id’] variable to get the meta value.
Example #2 – filter by calendar id/location
You can use the additional search field to display different calendars based on the field’s value. In the example below, if “City” is selected, only calendars 1, 2 and 3 will be returned if the dates are available. If “Beach” is selected, calendars 4, 5 and 6 will be returned.
Please note that the code provided is just a sample to explain the functionality, you will need to adapt this code to work with your website setup.