Hi, the js_options
parameter is used for displaying only. To store multiple values of taxonomies, you should add 'multiple' => true
to the field's param, as following (I also rewrite the parameters to match new version of Meta Box):
array(
'id' => 'event_category',
'type' => 'taxonomy',
'taxonomy' => 'event-categories',
'field_type' => 'select_advanced',
'query_args' => array(),
'js_options' => array( 'multiple' => true, ),
'multiple' => true,
'placeholder' => 'Select ...',
'columns' => '4',
'tab' => 'general',
),