script.js

var btn1 = document.getElementById("btn1");
var btn2 = document.getElementById("btn2");
var main = document.getElementById("main");
var myList = document.getElementById("list");
var ul = document.getElementsByTagName("ul");
var story = myList.getElementsByClassName("item");
var popup = document.getElementsByClassName("popup")[0];
var close = document.querySelector(".close");



function addItem() {
	var newLi = document.createElement("li");
	newLi.innerHTML = "Новая задача";
	newLi.className = "item";
	myList.appendChild(newLi);
	popup.style.display = "none";
}
function delItem() {
	myList.removeChild(story[0]);

	if ( story.length == 0 ) {
		popup.style.display = "block";
	}
}
function closePopup() {
	popup.style.display = "none";
}

close.addEventListener("click", closePopup);
btn1.addEventListener("click", addItem);
btn2.addEventListener("click", delItem);

// close.addEventListener("click", closePopup);