* </p>
 *
 */
public class HtmlXpathExtractor extends AbstractXmlExtractor {
    /**
     * Regular expression pattern to match the charset attribute in the meta tag of HTML documents.
     * The pattern captures the charset value specified in the content attribute of the meta tag.
     * Example: &lt;meta http-equiv="Content-Type" content="text/html; charset=UTF-8"&gt;

```xml
<!-- crawler.xml -->
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE components PUBLIC "-//DBFLUTE//DTD LastaDi 1.0//EN"
    "http://dbflute.org/meta/lastadi10.dtd">
<components namespace="fessCrawler">
    <component name="crawler" class="org.codelibs.fess.crawler.Crawler" instance="prototype"/>