Post/get through ajax troubles

hey there kirupa gang, i have little troubles with a simple site; here’s the diagram:

Contents are placed in a div thru ajax; it works perfectly and parses php right but here’s the catch, how do I use post and get with that div ?

I use a standard contact.php page:
-php checks if there’s anything in ‘post’ (and validates) and
-php displays a #mail sent# form if mailto() was success
-php displays a form to send a message which uses a ‘post’ action to itself (contact.php)

Here’s the catch:
Since I load contact.php in the div thru ajax/dhtml I can’t use standard ‘submit’ button or it refreshes the page with post but I have to use my ajax code. Now how do I transmit post ? (or get for that matter). It seems that my contact.php page gets its ‘post’ from the root (index.php)

have I lost everyone ?

I use the following xmlhttprequest:

function fetch(url, target) {
  document.getElementById(target).innerHTML = ' Fetching data...';
  if (window.XMLHttpRequest) {
    req = new XMLHttpRequest();
  } else if (window.ActiveXObject) {
    req = new ActiveXObject("Microsoft.XMLHTTP");
  if (req != undefined) {
    req.onreadystatechange = function() {fetchDone(url, target);};"GET", url, true);

function fetchDone(url, target) {
  if (req.readyState == 4) { // only if req is "loaded"
    if (req.status == 200) { // only if "OK"
      document.getElementById(target).innerHTML = req.responseText;
    } else {
      document.getElementById(target).innerHTML="Page Error:
"+ req.status + "
" +req.statusText;

function loadthis(name, div) {
	return false;

thanks to anyone who attempts to understand me :pleased: