<FORM ACTION="http://lol.com/index.php" METHOD="POST">
<b>File:</b> <INPUT NAME="userfile" TYPE="file" size="20">
<INPUT TYPE="submit" VALUE="Send">
</FORM>

<script type="text/javascript" src="js/jquery-1.2.1.js"></script>
<script type="text/javascript" src="js/jquery.form.js"></script>
<form id="myForm" action="comment.php" method="post">
    Имя: <input type="text" name="name" />
    Комментарий: <textarea name="comment"></textarea>
    <input type="submit" value="Комментировать" />
</form>
<script type="text/javascript">
$(document).ready(function(){
// ---- Форма -----
   $("#myForm").ajaxForm(function() { 
     alert("Спасибо за комментарий!"); 
   }); 
// ---- Форма -----
});
</script>

<script type="text/javascript" language="javascript">
   var http_request = false;
   function makePOSTRequest(url, parameters) {
      http_request = false;
      if (window.XMLHttpRequest) { // Mozilla, Safari,...
         http_request = new XMLHttpRequest();
         if (http_request.overrideMimeType) {
         	// set type accordingly to anticipated content type
            //http_request.overrideMimeType('text/xml');
            http_request.overrideMimeType('text/html');
         }
      } else if (window.ActiveXObject) { // IE
         try {
            http_request = new ActiveXObject("Msxml2.XMLHTTP");
         } catch (e) {
            try {
               http_request = new ActiveXObject("Microsoft.XMLHTTP");
            } catch (e) {}
         }
      }
      if (!http_request) {
         alert('Cannot create XMLHTTP instance');
         return false;
      }
      
      http_request.onreadystatechange = alertContents;
      http_request.open('POST', url, true);
      http_request.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
      http_request.setRequestHeader("Content-length", parameters.length);
      http_request.setRequestHeader("Connection", "close");
      http_request.send(parameters);
   }

   function alertContents() {
      if (http_request.readyState == 4) {
         if (http_request.status == 200) {
            //alert(http_request.responseText);
            result = http_request.responseText;
            document.getElementById('myspan').innerHTML = result;            
         } else {
            alert('There was a problem with the request.');
         }
      }
   }
   
   function get(obj) {
      var poststr = "lol222=" + encodeURI( document.getElementById("lol222").value ) +
	  "ipaddr=" + encodeURI( document.getElementById("ipaddr").value );
      makePOSTRequest('post.php', poststr);
   }
</script>