//makes a http request to a script to return data in real time
// used as follows:
//
//  makeHttpRequest(url, funct);  
//
// where funct is a function that accepts one argument  
// which contains the return from the server (if successful)
function makeHttpRequest(url, callback_function, return_xml)
{
 var http_request, response, i;

 var activex_ids = [
   'MSXML2.XMLHTTP.3.0',
   'MSXML2.XMLHTTP',
   'Microsoft.XMLHTTP'
 ];

 if (window.XMLHttpRequest) { // Mozilla, Safari, IE7+...
   http_request = new XMLHttpRequest();
   if (http_request.overrideMimeType) {
     //http_request.overrideMimeType('text/xml');
   }
 } else if (window.ActiveXObject) { // IE6 and older
   for (i = 0; i < activex_ids.length; i++) {
     try {
       http_request = new ActiveXObject(activex_ids[i]);
     } catch (e) {}
   }
 }

 if (!http_request) {
   alert('Unfortunately your browser doesn’t support this feature.');
   return false;
 }

 http_request.onreadystatechange = function() {
   if (http_request.readyState !== 4) {
       // not ready yet
       return;
   }
   if (http_request.status !== 200) {
     // ready, but not OK
     alert('There was a problem with the request.(Code: ' + http_request.status + ')');
     return;
   }
   if (return_xml) {
     response = http_request.responseXML;
   } else {
     response = http_request.responseText;
   }
   // invoke the callback
   callback_function(response);
 };

 http_request.open('GET', url, true);
 http_request.send(null);
}

function f_scrollTop() {
	return f_filterResults (
		window.pageYOffset ? window.pageYOffset : 0,
		document.documentElement ? document.documentElement.scrollTop : 0,
		document.body ? document.body.scrollTop : 0
	);
}
function f_filterResults(n_win, n_docel, n_body) {
	var n_result = n_win ? n_win : 0;
	if (n_docel && (!n_result || (n_result > n_docel)))
		n_result = n_docel;
	return n_body && (!n_result || (n_result > n_body)) ? n_body : n_result;
}