What's the best way to transfer a large html page over ajax?

I'm currently making a cms and stuggling to work out why I'm getting the 414 Server Error which means that the URI is too long when I'm using POST to send all my data over via AJAX.



If you want the look at the code, please ask.What's the best way to transfer a large html page over ajax?
Yes I need to see the code. (You can email me privately if you like.)

When using the post method, content is sent by passing it as an argument to the send method,

xmlhttp.open("POST","../ajax.php", true);
xmlhttp.send("title=" + title + "%26amp;page=" + page + "%26amp;menu=" + menu + "%26amp;content=" + content);