var x_cookieName = "xyzzy"; // unique

function detect_cookies()
{
// detect if cookies are being blocked: set, then check.

var x_expires = new Date(); x_expires.setFullYear(x_expires.getFullYear()+1); // testing persistent cookies
xDeleteCookie(x_cookieName); // don't get false positive

// add path if you want to. drop expires for session cookie. drop domain for default domain test.
document.cookie = x_cookieName + "=test; expires=" + x_expires.toGMTString() + "; " 

// now look for it.
var x_cookieString = document.cookie || "";
var x_cookies = x_cookieString.split(/\s*;\s*/);
var x_found = 0;
for (var i in x_cookies) {
    var cookie = x_cookies[i];
    var dough = cookie.split(/\s*=\s*/);
    if (dough[0] == x_cookieName) { x_found = 1; break; }
}

// ensure it's gone
xDeleteCookie(x_cookieName);

// do whatever you want with x_found bool
if (x_found == 1) {
    null;
}
else {
      alert("COOKIES DISABLED!\n\nIn order to access all the services of this site, please enable cookies on your browser");
     }
}

function xDeleteCookie(name) {
    var oldDate = new Date(1970, 1, 1);
    document.cookie = x_cookieName + "=0; expires=" + oldDate.toGMTString();
}