function createXmlHttpRequestObject()
{
	var xmlHttp;

	try	{
		xmlHttp = new XMLHttpRequest();
	}
	catch(e) {
		var xmlHttpVersions = new Array('MSXML2.XMLHTTP.6.0',
										'MSXML2.XMLHTTP.5.0',
										'MSXML2.XMLHTTP.4.0',
										'MSXML2.XMLHTTP.3.0',
										'MSXML2.XMLHTTP',
										'Microsoft.XMLHTTP');
		for(var i=0; i<xmlHttpVersions.length && !xmlHttp; i++)	{
			try	{
				xmlHttp = new ActiveXObject(xmlHttpVersions[i]);
			}
			catch(e) {}
		}
	}

	if(!xmlHttp)
		alert("Vissa funktioner på denna sida fungerar inte eftersom din webbläsare är för gammal.");
	else
		return xmlHttp;
}

var req = createXmlHttpRequestObject();

function navigate(year,month)
{
        var url = "include/calendar.php?year="+year+"&month="+month;

        req.open("GET", url, true);
        req.onreadystatechange = callback;
        req.send(null);
}

function callback()
{
        if(req.readyState == 4)
		{
                if(req.status == 200)
				{
                	response = req.responseText;
                    document.getElementById("calendar").innerHTML = response;
                }
				else
				{
                    alert("There was a problem retrieving the data:\n" + req.statusText);
                }
        }
}