Ask users to enter their name and store it in a cookie.

cookieUserInfo.js

function getCookieVal (offset) {
    var endstr = document.cookie.indexOf (";", offset);
    if (endstr == -1) {
        endstr = document.cookie.length;
    }

    return unescape(document.cookie.substring(offset, endstr));
}

function getCookie (name) {
    var arg = name + "=";

    var argLength = arg.length;
    var cookieLength = document.cookie.length;

    var i = 0;
    while (i < cookieLength) {
        var j = i + argLength;
        if (document.cookie.substring(i, j) == arg) {
            return getCookieVal(j)
        } else {
            i++;
        }
    }

    return null;
}

function setCookie(name, value, expires, path, domain, secure) {
    document.cookie = name + "=" + escape(value) +
        (expires ? ("; expires=" + expires.toGMTString()) : "") +
        (path ? ("; path=" + path) : "") +
        (domain ? ("; domain=" + domain) : "") +
        (secure ? "; secure" : "");
}

// get a date that is exactly one week away from today
function getWeekFromToday() {
    var d = new Date();
    d.setDate(d.getDate() + 7);
    return d;
}

(function() {
    var username = getCookie('username');

    if( !username ) {
        username = prompt("Please enter your name", "");

        if (username != null) {
            setCookie('username', username, getWeekFromToday());
        }
    }
}());