Can'；在PHP中无法使用字符编码

我已经把阅读youtube视频标签的小工具放在一起了。

它适用于ASCI字符，但UTF字符显示不可读。 我找不到问题。

-

将使用UTF-8编码的ISO-8859-1字符的字符串转换为 单字节ISO-8859-1

---

使用

utf8\u解码

输出：

echo utf8_decode(substr($meta_val,1)) ;

---

将

内容类型设置为
utf-8

header('Content-Type: text/html; charset=utf-8');


完整代码：

header('Content-Type: text/html; charset=utf-8');
$_POST['fn']='https://www.youtube.com/watch?v=OgAt8Ehg0eo';
if(isset($_POST['fn']) && $_POST['fn'] != ''){
    $url = htmlentities($_POST['fn']);
    $page_content = file_get_contents('https://www.youtube.com/watch?v=OgAt8Ehg0eo');


    $dom_obj = new DOMDocument();
    if($dom_obj->loadHTML($page_content)){

        $dom_obj->loadHTML($page_content);
        $meta_val = '';

        foreach($dom_obj->getElementsByTagName('meta') as $meta) {

            if($meta->getAttribute('property')=='og:video:tag'){ 

                $meta_val = $meta_val.','.$meta->getAttribute('content');
            }
        }
        echo utf8_decode(substr($meta_val,1)) ;
    }
    else{
        echo "Invalid Url!";
    }
}
else{
    echo "Empty Url!";
}

header('Content-Type: text/html; charset=utf-8');
$_POST['fn']='https://www.youtube.com/watch?v=OgAt8Ehg0eo';
if(isset($_POST['fn']) && $_POST['fn'] != ''){
    $url = htmlentities($_POST['fn']);
    $page_content = file_get_contents('https://www.youtube.com/watch?v=OgAt8Ehg0eo');


    $dom_obj = new DOMDocument();
    if($dom_obj->loadHTML($page_content)){

        $dom_obj->loadHTML($page_content);
        $meta_val = '';

        foreach($dom_obj->getElementsByTagName('meta') as $meta) {

            if($meta->getAttribute('property')=='og:video:tag'){ 

                $meta_val = $meta_val.','.$meta->getAttribute('content');
            }
        }
        echo utf8_decode(substr($meta_val,1)) ;
    }
    else{
        echo "Invalid Url!";
    }
}
else{
    echo "Empty Url!";
}