检查是否选择了下拉菜单 - Wordpress

Question

如果未选择$answer，我希望artist_name设置drop_artists。我也试过if( isset($_POST['drop_artists']) ) {但没有运气。我做错了什么？

if( $_POST['drop_artists'] != '' ) {
            $answer = $_POST['drop_artists'];
        }else{
            $answer = $_POST['artist_name'];
        }

形式：

<form method="post" action="" id="artists-form">

        <?php 
        $args = array(
            'show_option_all' => 'Artists',
            'hierarchical' => 1,
            'child_of' => 406,
            'orderby' => 'name',
            'name' => 'drop_artists',
            'hide_empty' => 0
        );
        wp_dropdown_categories($args); ?>

<h3 class="widget-title">Can't find the artist? Fill in below:</h3>

<input type="text" name="artist_name" value="" size="45" id="input-title"/>

<input id="submitButton" class="subput" type="submit" name="submit" value="Submit"/>
</form>

Answer 1

检查$_POST['drop_artists'] != 0