public static Element appendChild(Node node, String tagName) {
		Document doc = (node instanceof Document) ? (Document) node : node.getOwnerDocument();
		Element child = doc.createElement(tagName);
		node.appendChild(child);
		return child;
	}
public static Element appendChild ( Node node , String tagName ) { Document doc = ( node instanceof Document ) ? ( Document ) node : node . getOwnerDocument ( ) ; Element child = doc . createElement ( tagName ) ; node . appendChild ( child ) ; return child ; }
在已有节点上创建子节点

@param node 节点
@param tagName 标签名
@return 子节点
@since 4.0.9