Allows you to use arrow keys to navigate on XKCD

xkcd-enhancements.user.js

// ==UserScript==
// @name         XKCD Arrow Keys
// @namespace    http://github.com/karlding
// @version      0.1
// @description  Allows you to use arrow keys to navigate on XKCD
// @author       Karl Ding
// @match        http*://xkcd.com/*
// @grant        none
// ==/UserScript==

// look mom! no jQuery
window.addEventListener('keydown', function(e) {
    var q = document.querySelector.bind(document);

    switch (e.keyCode) {
        case 74: case 37: // left, j
            q("a[rel=prev]").click();
            break;
        case 76: case 39: // right, l
            q("a[rel=next]").click();
    }
});