function getElementSafe(id)
{
    var retval;
    if (document.getElementById) {
        retval = document.getElementById(id);
    }
    else if (document.all) {
        retval = document.all[id];
    }
    else if (document.layers) {
        retval = document.layers[id];
    }
    return retval;
}

function getCookie(c_name)
{
    if (document.cookie.length > 0) {
        c_start = document.cookie.indexOf(c_name + "=");
        if (c_start != -1) { 
            c_start = c_start + c_name.length + 1; 
            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 setCookie(c_name, value, expiredays)
{
    var exdate = new Date();
    exdate.setDate(exdate.getDate() + expiredays);
    document.cookie=c_name + "=" + escape(value) +
        ((expiredays==null) ? "" : ";expires=" + exdate.toGMTString());
}

function setImage()
{
    var lastImage = getCookie('arborviewLastImageId');
    if (lastImage != null && lastImage != "") {
        var imageId = getElementSafe('headerImage');
        if (lastImage == '0') {
            setCookie('arborviewLastImageId', '1', 365);
            imageId.src = "Shared/Images/hdr_wind.jpg";
        }
        else {
            setCookie('arborviewLastImageId', '0', 365);
        }
    }
    else {
        setCookie('arborviewLastImageId', '0', 365);
    }
}

window.onload = function() { setImage(); };