Update app.js

app.js

@@ -0,0 +1,61 @@
+document.addEventListener("click", function () {
+    console.log("you've clicked the document");
+});
+
+document.addEventListener("click", function () {
+    // select the element
+    const mainHeading = document.querySelector("h1");
+
+    // change its background color to red
+    mainHeading.style.backgroundColor = "red";
+});
+
+// create a new div element
+const myCustomDiv = document.createElement("div");
+
+for (let i = 1; i <= 200; i++) {
+    // create a new paragraph element
+    const newElement = document.createElement("p");
+
+    // add text to the paragraph
+    newElement.textContent = "This is paragraph number " + i;
+
+    // register an event listener to the paragraph element
+    newElement.addEventListener("click", function respondToTheClick(evt) {
+        console.log("A paragraph was clicked.");
+    });
+
+    // append the paragraph to the new div element
+    myCustomDiv.appendChild(newElement);
+}
+
+// append the new div element to the page
+document.body.appendChild(myCustomDiv);
+
+// favorite buttons
+const ndList = document.querySelectorAll(".card--nanodegree__title");
+ndList.forEach(function (nd) {
+    const button = document.createElement("button");
+    button.textContent = "Add to Favorites";
+    button.classList = "button button--primary";
+    nd.appendChild(button);
+});
+
+function toggleFavorite(event) {
+    const target = event.target;
+    if (target.nodeName === "BUTTON") {
+        event.preventDefault();
+        if (target.textContent.startsWith("Add")) {
+            event.target.textContent = "Remove from favorites";
+            const fav = document.createElement("p");
+            fav.textContent = "⭐ ⭐ ⭐ ";
+            target.parentElement.appendChild(fav);
+        } else {
+            event.target.textContent = "Add to favorites";
+            target.nextSibling.remove();
+        }
+    }
+}
+
+const ndsContainer = document.querySelector(".list-nanodegrees");
+ndsContainer.addEventListener("click", toggleFavorite);