Vattu Page Turner

// ==UserScript==
// @name         VattuPageturner
// @require      https://ajax.googleapis.com/ajax/libs/jquery/1.7.2/jquery.min.js
// @version      1
// @description  Arrow keys turn pages of Vattu, thanks/apologies to Billy King
// @include      http://*rice-boy.com/vattu/*
// ==/UserScript==
//Returns variable from URL stored with PHP GET format in variable str
function getURLVars(str) {
    var vars = {};
    var parts = window.location.href.replace(/[?&]+([^=&]+)=([^&]*)/gi, function(m,key,value) {
        vars[key] = value;
    });
    return vars[str];
}
function main() {
    $('title').append(' - '+getURLVars('c'));
    (new Image()).src = (parseInt(getURLVars('c'))-1)+'.png';
    (new Image()).src = (parseInt(getURLVars('c'))+1)+'.png';
    $(document).keydown(function(e) {
        switch(e.which) {
            case 37:
                window.location='index.php?c='+(parseInt(getURLVars('c'))-1);
                break;
            case 39:
                window.location='index.php?c='+(parseInt(getURLVars('c'))+1);
                break;
        }
    });
}
$(document).ready(main);