<script type="text/javascript">

var XHreq = false;

function SetRequest() {
  if(window.XMLHttpRequest) XHreq = new XMLHttpRequest();	// Firefox, Safari, Opera
  else if(window.ActiveXObject) {
    try { XHreq = new ActiveXObject("Msxml2.XMLHTTP");	// IE 5
    } catch(e) {
      try { XHreq = new ActiveXObject("Microsoft.XMLHTTP");	// IE 6
      } catch(e) { }
    }
  }
	
  return XHreq;
}


function XHreqSuccess() {
  success = false;
  if(XHreq.readyState==4 && XHreq.status==200) success = true;
  return success;
}


function starteScript(value) {
  SetRequest();

  if(XHreq) {
    var url = "dein_script.php";
    XHreq.open("post",url,true);
    XHreq.setRequestHeader("Content-Type","application/x-www-form-urlencoded");
    XHreq.send("parameter="+value);
    XHreq.onreadystatechange = function() {
      if(XHreqSuccess) { Hier verarbeitest Du das Ergebnis ! }
    }
  }
}


</script>