void outerHtmlTail(StringBuilder accum, int depth, Document.OutputSettings out) {
        if (!(childNodes.isEmpty() && tag.isSelfClosing())) {
            if (out.prettyPrint() && (!childNodes.isEmpty() && (
                    tag.formatAsBlock() || (out.outline() && (childNodes.size()>1 || (childNodes.size()==1 && !(childNodes.get(0) instanceof TextNode))))
            )))
                //换行并调整缩进
                indent(accum, depth, out);
            accum.append("</").append(tagName()).append(">");
        }
    }