Ajax: Submit method

I'm used to using Ajax, however, the method I use usually requires that I request a php file that queries my database. The thing is that I need to call the php document this way:

http.open("GET", url, true);

I would rather use a "post" method instead of the "get" method - makes it easier to pass data to the target page. Is there a way to do so using Ajax?

Please help.

 

See my code:

"PHP/AJAX POST Example with responseText"

here:

http://ajaxforums.net/index.php?topic=871.0