var xmlhttp;

function getCookie(c_name)
{
    if (document.cookie.length>0)
    {
        var c_start=document.cookie.indexOf(c_name + "=");
        if (c_start != -1)
        {
            c_start = c_start + c_name.length + 1;
            var c_end = document.cookie.indexOf(";",c_start);
            if (c_end == -1)
            {
                c_end=document.cookie.length;
            }
            return unescape(document.cookie.substring(c_start,c_end));
        }
    }
    return "";
}


function changeMonth(str)
{
    var y = getCookie("y");
    if (y == null || y == "")
    {
        // Default to current year if cookie is not set
        var dateNow = new Date();
        y = dateNow.getFullYear();
    }
    xmlhttp = GetXmlHttpObject();
    if (xmlhttp == null)
    {
        alert ("Browser does not support HTTP Request");
        return;
    }
    var url = "../varausjarjestelma.php";
    url = url+"?m=" + str;
    url = url+"&y=" + y;
    url = url+"&sid=" + Math.random();
    document.cookie = "m" + "=" + escape(str);
    xmlhttp.onreadystatechange = stateChanged;
    xmlhttp.open("GET", url, true);
    xmlhttp.send();
}

function changeYear(str)
{
    m = getCookie("m");
    if (m == null || m == "")
    {
        // Default to January if cookie is not set
        m = "1";
    }
    xmlhttp = GetXmlHttpObject();
    if (xmlhttp == null)
    {
        alert ("Browser does not support HTTP Request");
        return;
    }
    var url = "../varausjarjestelma.php";
    url = url+"?m=" + m;
    url = url+"&y=" + str;
    url = url+"&sid=" + Math.random();
    document.cookie = "y" + "=" + escape(str);
    xmlhttp.onreadystatechange = stateChanged;
    xmlhttp.open("GET", url, true);
    xmlhttp.send();
}

function stateChanged()
{
    if (xmlhttp.readyState == 4)
    {
        document.getElementById("calendar-refresh").innerHTML = xmlhttp.responseText;
    }
}

function GetXmlHttpObject()
{
    if (window.XMLHttpRequest)
    {
        // IE7+, Firefox, Chrome, Opera, Safari
        return new XMLHttpRequest();
    }
    if (window.ActiveXObject)
    {
        // IE6, IE5
        return new ActiveXObject("Microsoft.XMLHTTP");
    }
    return null;
}