var UA = navigator.userAgent;
var safari2Mac = (UA.indexOf('Mac') != -1 && UA.indexOf('Version/') == -1 && UA.indexOf('Safari/') != -1);
if (safari2Mac) {
    var dot1 = location.hostname.lastIndexOf(".");
    var domainPart = location.hostname.substring(0,dot1);
    var dot2 = domainPart.lastIndexOf(".");
    if (domainPart.substring(dot2+1,dot1)=="co") {
        // handle  domain.co.uk  or  domain.co.nz  etc
        domainPart = location.hostname.substring(0,dot2);
        dot2 = domainPart.lastIndexOf(".");
    }
    document.domain=location.hostname.substring(dot2+1);
}