function updateSize() {
	var xhr_object = null;
	if(window.XMLHttpRequest) xhr_object = new XMLHttpRequest();
	else if(window.ActiveXObject) xhr_object = new ActiveXObject("Microsoft.XMLHTTP");
	else {
		alert("Votre navigateur ne supporte pas les objets XMLHTTPRequest...");
		return;
	}

	var method   = "GET";
	var filename = "/getsize.pl";
	var f = document.getElementsByTagName("FORM")[0];
	var s1       = "";
	var s2       = f.elements["territoire"].value;
	var s3       = f.elements["l"].value;

	for (var i=0; i<f.pc.length;i++) {
		if (f.pc[i].checked) {
			s1 = f.pc[i].value
		}
	}
	var data     = null;
	if(s1 != "" && s2 != "" && s3 != "")
	{
	   data = "pc="+s1+"&territoire="+s2+"&l="+s3;
	   filename += "?"+data;
	}
	xhr_object.open(method, filename, true);
	xhr_object.onreadystatechange = function() {
	   if(xhr_object.readyState == 4) {
	      document.getElementById("sizeSpan").innerHTML = xhr_object.responseText;
	   }
	}
	xhr_object.send(null);
}