```php
<?php
function fetch() {
    $url = '
https://steamcommunity.com/app/200210';    $ch = curl_init();
    curl_setopt_array($ch, [
        CURLOPT_RETURNTRANSFER => true,
        CURLOPT_TIMEOUT => 3,
        CURLOPT_URL => $url,
        CURLOPT_HEADER => [
            'User-Agent' =>'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/106.0.0.0 Safari/537.36',
        ],
    ]);
    return curl_exec($ch);
}
function parseHTML( $html)  {
    if (!$html) {
        return '';
    }
    libxml_use_internal_errors(true);
    $dom = new DOMDocument('1.0');
    $dom->preserveWhiteSpace = true;
    $dom->loadHTML($html);
    $xpath =new DOMXPath($dom);
    $node = $xpath->query('//span[@class="apphub_NumInApp"]');
    $text = $node->item(0)->textContent;
    // 有可能是中文,以空格分隔
    list($onlineCount, $left) = sscanf($text, '%s %s');
    return str_replace( ',', '', $onlineCount);
}
$result = parseHTML(fetch());
var_dump($result);
```