Storing cookies

You must have heard of cookies before. They're a browser-based storage mechanism as old as the Internet, and they are often comically described in movies. Here's how we use them:

document.cookie = "pages=all_the_pages";
document.cookie = "current=current_page_id";

The document.cookie parameter works as a temporary string store. You can keep adding new strings, where the key and value are separated by =, and they will be stored beyond a page reload, that is, until you reach the limit of how many cookies your browser will store per domain. If you set document.cookie multiple times, multiple cookies will be set.

You can read the cookies back again, with a function like this:

var cookies = {};

function readCookie(name) {
    var chunks = document.cookie.split("; ");

    for (var i = chunks.length - 1; i >= 0; i--) {
        var parts = chunks[i].split("=");
        cookies[parts[0]] = parts[1];
    }

    return cookies[name...