Add node to existing XML file

[troyboy]

Here's my current XML file (books.xml):\[code\]<?xml version="1.0"?><books> <book> <isbn>123456789098</isbn> <title>Harry Potter</title> <author>J K. Rowling</author> <edition>1</edition> </book></books>\[/code\]Please note that in this case, the edition is a number from 1 to 99, and that the ISBN has a length of 12 digits, contrary to the real-world concept of the book attribute.I have an "add book" form and I want to save the collected data from that form (using post) by appending the new book to the already-existing XML file. What would be the best way to do this, in PHP? I am confused as to how to do it because the way I did it works half and half: either it saves an empty node or does nothing at all.\[code\]/**************************************code snippet of results.php*************************************/$doc = new DOMDocument();$doc->load('books.xml');$nodes = $doc->getElementsByTagName('books');if($nodes->length > 0){ $b = $doc->createElement( "book" ); $isbn = $doc->createElement( "isbn" ); $isbn->appendChild( $doc->createTextNode( $book['isbn'] )); $b->appendChild( $isbn ); $title = $doc->createElement( "title" ); $title->appendChild( $doc->createTextNode( $book['title'] )); $b->appendChild( $title ); $author = $doc->createElement( "author" ); $author->appendChild( $doc->createTextNode( $book['author'] )); $b->appendChild( $author ); $edition = $doc->createElement( "edition" ); $edition->appendChild( $doc->createTextNode( $book['edition'] )); $b->appendChild( $edition ); $doc->appendChild( $b ); } $doc->save('books.xml');\[/code\]Thank you for your help.