http://www.developer.com/lang/php/article.php/3897851/A-Workaround-for-XML-Files-Too-Big-for-Ajax-to-Handle.htm
A simple way to transfer XML documents onto a server is to use an Ajax-driven Web interface to upload the files. However, this approach won't work for huge XML files because Ajax doesn't support uploading of files that large. In her PHPBuilder.com article, Octavia Andreea Anghel demonstrates an innovative solution for transferring huge XML documents on the server via a Web interface using Ajax and the GET method. The solution works like this:
A Workaround for XML Files Too Big for Ajax to Handle
August 10, 2010
Read the full story at PHPBuilder:
Transferring Huge XML Documents in PHP with an Ajax-driven Web Interface