PHPHtmlParser\Dom::detectCharset PHP Method

    protected function detectCharset()
    {
        // set the default
        $encode = new Encode();
        $encode->from($this->defaultCharset);
        $encode->to($this->defaultCharset);
        if (!is_null($this->options->enforceEncoding)) {
            //  they want to enforce the given encoding
            $encode->from($this->options->enforceEncoding);
            $encode->to($this->options->enforceEncoding);
            return false;
        }
        $meta = $this->root->find('meta[http-equiv=Content-Type]', 0);
        if (is_null($meta)) {
            // could not find meta tag
            $this->root->propagateEncoding($encode);
            return false;
        }
        $content = $meta->content;
        if (empty($content)) {
            // could not find content
            $this->root->propagateEncoding($encode);
            return false;
        }
        $matches = [];
        if (preg_match('/charset=(.+)/', $content, $matches)) {
            $encode->from(trim($matches[1]));
            $this->root->propagateEncoding($encode);
            return true;
        }
        // no charset found
        $this->root->propagateEncoding($encode);
        return false;
    }