code: var xmlhttp = new ActiveXObject("Microsoft.XMLHTTP");
xmlhttp.open("POST", 'http://www.url.com/script.php', true);
xmlhttp.setRequestHeader("Content-Type", "application/x-www-form-urlencoded"); //if posting to a html form
xmlhttp.send('var1=content1&var2=content2&varX=etc');
xmlhttp.onreadystatechange = function(){
if ((xmlhttp.readyState == 4) && (xmlhttp.status == 200)) {
var postResponse = xmlhttp.responseText;
//fsResponse contains the result of the POST, so the URL is in there somewhere, depending on what method you use in your online form to redirect (may be javascript, php's header(), etc)
}
}