A javascript bot for http://orteil.dashnet.org/cookieclicker/

CookieClickerBot.js

var purchaseSleep = 500;
var cookieClickSleep = 5;
var goldCookieClickSleep = 200;
var sugarLumpClickSleep = 24*60*60*1000;
var maxUpgradeWait = 10*60;
var priorityUpgrades = [476];
var excludeUpgrades = ["toggle","tech"];

function buyBestThing(){
    var myCookies = Game.cookies;
    var upgradeId = getBestUpgradeId(myCookies);
    var buildingId = getBestBuildingId(myCookies);

    if (shouldBuyUpgrade(upgradeId, Game.cookiesPs)) {
        getUpgradeDom(upgradeId).click();
    } else if (shouldBuyBuilding()){
        getBuildingDom(buildingId).click();
    }

    setTimeout(buyBestThing, purchaseSleep);
}

function shouldBuyUpgrade(upgradeId, cookiesPerSecond){
    if (upgradeId == -1)
        return false;
    var upgrade = getUpgrade(upgradeId);
    return upgrade.getPrice() <= maxUpgradeWait * cookiesPerSecond;
}

function shouldBuyBuilding(){
    return document.getElementById("storeBulkBuy").classList.contains("selected")
}

function getBestBuildingId(currentCookies){
    var lastBuildingId = getLastUnlockedBuildingId();
    var expensiveBuildingId = 0;
    var expensivePrice = 0;

    for(var i = lastBuildingId; i >= 0; i--){
        var currentPrice = getBuilding(i).price;
        if (expensivePrice < currentPrice && currentPrice < currentCookies){
            expensiveBuildingId = i;
            expensivePrice = currentPrice;
        }
    }

    return expensiveBuildingId;
};

function getBestUpgradeId(currentCookies){
    var minUpgrade = -1;
    var minPrice = Number.MAX_VALUE;
    for (var i = 0; i < 100; i++){
        if (getUpgradeDom(i) == null){
            break;
        }
        var upgrade = getUpgrade(i);
        var currentPrice = upgrade.getPrice();
        if (excludeUpgrades.includes(upgrade.pool)) {
            continue;
        }
        if (priorityUpgrades.includes(upgrade.id)){
            return i;
        }
        if (minPrice > currentPrice){
            minUpgrade = i;
            minPrice = currentPrice;
        }
    }
    return minUpgrade;
};

function getLastUnlockedBuildingId(){
    var maxBuildingId = 15;
    for(var buildingId = maxBuildingId; buildingId >= 0; buildingId--){
        if(isUnlocked(buildingId)) {
            return buildingId;
        };
    };
}

function isUnlocked(buildingId){
    return getBuildingDom(buildingId).classList.contains("unlocked")
}

function getBuilding(index){
    return Game.ObjectsById[index];
}

function getBuildingDom(index){
    return document.getElementById("product" + index);
}

function getUpgrade(index){
    var dom = getUpgradeDom(index);
    var clickFunction = dom.onclick.toString();
    var upgradeId = clickFunction.substring(clickFunction.indexOf("[") + 1,clickFunction.indexOf("]"));
    return Game.UpgradesById[upgradeId];
}

function getUpgradeDom(index){
    return document.getElementById("upgrade" + index);
}

function clickBigCookie() {
    document.getElementById('bigCookie').click();
    setTimeout(clickBigCookie, cookieClickSleep);
} 

function clickGoldCookie() {
    var cookies = document.getElementsByClassName('shimmer');
    for(var i = 0; i<cookies.length; i++)
        cookies[i].click();
    setTimeout(clickGoldCookie, goldCookieClickSleep);
}

function spendSugarLumpOnCursorUpgrade() {
    var upgradeButton = document.getElementById("productLevel0");
    upgradeButton.click();
    setTimeout(spendSugarLumpOnCursorUpgrade, sugarLumpClickSleep);
}

clickBigCookie();
clickGoldCookie();
spendSugarLumpOnCursorUpgrade();
buyBestThing();