def __init__(self, html,isForeign = True, url=None):
        """Generate the document
        :param html: string of the html content.
        :param url: url of the html
        """
        self.url = url
        self.html = html
        self.link_num = 0
        self.link_text_len = 0
        self.total_text_tag_num = 0
        self.total_text_len = 0
        self.text_tag_num = 0
        self.text_tag_text_len = 0
        self.is_foreign = isForeign