如果该代码的功能没有错误,如何关闭?

how to close if fuction of that code without error?

我创建的这段代码是为了仅为帖子添加元关键字标签 header 并排除所有网站页面(主页、关于、联系、博客等) 我将此代码添加到 function.php,每次我遇到错误,如果使用 endif 函数我必须关闭,每次我尝试我都遇到错误..所以请帮助

add_action('wp_head', function (){
  ?>
  <?php 
    if ( is_single() ) {
    echo get_post_meta( get_the_ID(), 'meta-head', true );  
  $postTags = get_the_tags();
  $tagNames = array();
  foreach($postTags as $tag) {
    $tagNames[] = $tag->name;          
      }
?>
<meta name="keywords" content="<?php echo implode($tagNames,","); ?>" />
  <?php
    }

您忘记关闭功能了

add_action('wp_head', function (){
  if ( is_single() ) { 
    echo get_post_meta( get_the_ID(), 'meta-head', true ); 
    $postTags = get_the_tags(); 
    $tagNames = array(); 
    foreach($postTags as $tag) { 
      $tagNames[] = $tag->name; 
     } 
     ?> 
     <meta name="keywords" content="<?php echo implode($tagNames,","); ?>" /> 
  <?php 
  }
 } // This one here