<script type="text/javascript">
var http = new XMLHttpRequest();
var url = "123.php";
var params = "lol=1";
http.open("POST", url, true);
http.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
http.onreadystatechange = function() {
if ( http.readyState == 4 ) {
document.body.innerHTML = http.responseText;
}
}
http.send(params);
</script>