function makeHttpRequest(url, callback_function, return_xml) {
	  var http_request = false;

	  if (window.XMLHttpRequest) { // Mozilla, Safari,...
			http_request = new XMLHttpRequest();
			if (http_request.overrideMimeType && return_xml == 'xml') {
				 http_request.overrideMimeType('text/xml');
			}
	  } 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('Unfortunately your browser doesn\'t support this feature.');
			return false;
	  }

	  http_request.onreadystatechange = function() {
			if (http_request.readyState == 4) {
				 if (http_request.status == 200) {
					  if (return_xml == 'xml') {
							eval(callback_function + '(http_request.responseXML)');
					  } else {
							eval(callback_function + '(http_request.responseText)');
					  }
				 } else {
					  alert('There was a problem with the request. (Code: ' + http_request.status + ')');
				 }
			}
	  }
	  http_request.open('GET', url, true);
	  http_request.send(null);
  }