Where can I find details of PDF form submittal options (actions)?

Could someone point me to some information that provides all the details of how a PDF form is submitted to the server and discusses the options for the action? This information must surely exist somewhere, but after two days of searching I cannot find it. I can find some information on the FDF action (which I cannot use) but no information whatsoever on the other actions including submit as HTML and submit a s complete PDF. I tried submitting with the "Submit as HTML" option to a PHP script that would show what is in the $_POST array, but this kicked an error in Acrobat reader, something about not being able to handle text/html content. I am bewildered and confused.

I am experienced with PHP (I used FPDF for one project) so a specific "how to" that is PHP oriented would be nice.

P.S., I looked at http://kb2.adobe.com/cps/325/325874.php, but it discussed only FDF and was of no help.