Javascript event listeners

// Visada grazins viena elementa
var button = document.getElementById("mygtukas");

// Visada grazins elementu masyva
var heading = document.querySelector("h1");
var photos = document.getElementsByClassName('nuotrauka');

for(var i = 0; i < photos.length; i++) {
    photos[i].addEventListener("click", changeColor);
}

heading.addEventListener("click", changeColor);

button.addEventListener("click", showAlert);

function showAlert() {
    alert("Sveikinu, tu laimejai iPhone");
}

function changeColor() {
    // this kintamasis grazina elementa kuris buvo paspaustas
    /* Informacija apie classList: https://developer.mozilla.org/en/docs/Web/API/Element/classList */
    this.classList.toggle("red");
}