function listCookies() {
    var theCookies = document.cookie.split(';');
    var aString = '';
    for (var i = 1 ; i <= theCookies.length; i++) {
        aString += i + ' ' + theCookies[i-1] + "\n";
    }
    return aString;
}

http://www.arachna.com/edu/tutorials/mini/cookies/javascript.html

List Cookies in Javascript

JavaScript