Calculate total time
add_filter(‘frm_validate_field_entry’, ‘calculate_time’, 11, 3); function calculate_time($errors, $field, $value){ if($field->id == 25){ //change 25 to the ID of the hidden or admin only field which will hold the calculation $start = strtotime($_POST[‘item_meta’][23]); //change 23 to the ID of the first field…Continue reading