JavaScript Academy · Lesson

Creating and Inserting Elements

Build new nodes with createElement and append.

Lesson 2 of 413 steps

Creating and Inserting Elements is a free JavaScript Academy lesson on CoddyKit. This is lesson 2 of 4. Any 3 lessons of this learning path are free to read in full — after that, CoddyKit PRO unlocks every lesson, plus hands-on practice with a built-in code editor and a 24/7 AI tutor. It is part of the JavaScript Academy learning path, and your progress syncs across the web and the CoddyKit app. The JavaScript Academy course includes 4 lessons in total.

Building New Elements

Instead of writing HTML strings, you can construct elements in code. This avoids XSS and gives you a real element reference to configure.

createElement

document.createElement makes a new, detached element. It exists in memory but is not yet in the page.

const li = document.createElement("li");
li.textContent = "New item";

Configuring Before Inserting

Set classes, attributes, and content while the element is still detached. It only becomes visible once you insert it.

const btn = document.createElement("button");
btn.textContent = "Save";
btn.className = "primary";

append

append adds nodes (or strings) as the last children of an element. It can take multiple arguments.

const list = document.querySelector("ul");
list.append(li);

prepend

prepend inserts nodes as the first children, pushing existing children down.

list.prepend(document.createElement("li"));

append Accepts Strings

Unlike the older appendChild, append can take plain strings and multiple arguments at once.

const p = document.createElement("p");
p.append("Hello, ", document.createElement("br"), "World");

appendChild

appendChild is the classic method. It accepts only one node and returns it, while append returns undefined.

const node = list.appendChild(document.createElement("li"));

insertBefore

insertBefore places a new node before a specific existing child, giving precise positioning.

const ref = list.children[1];
list.insertBefore(li, ref);

insertAdjacentElement

insertAdjacentElement inserts relative to an element using positions like beforebegin, afterbegin, beforeend, and afterend.

ref.insertAdjacentElement("beforebegin", li);

DocumentFragment for Batches

When adding many elements, build them in a DocumentFragment first, then insert once. This minimizes reflows and is faster.

const frag = document.createDocumentFragment();
for (let i = 0; i < 3; i++) {
  const item = document.createElement("li");
  item.textContent = "Row " + i;
  frag.append(item);
}
list.append(frag);

cloneNode

cloneNode(true) copies an element and its descendants, useful for templating repeated structures.

const copy = li.cloneNode(true);
list.append(copy);

Quick Check

Choose the best technique.

Answer it in the interactive lesson

Recap

Use createElement to build detached elements, configure them, then insert with append/prepend (strings allowed, multiple args), appendChild (single node), or insertBefore/insertAdjacentElement for precise positions. Batch many inserts through a DocumentFragment, and reuse structures with cloneNode(true).

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Frequently Asked Questions

Is the “Creating and Inserting Elements” lesson free?

Yes — any 3 lessons of the JavaScript Academy learning path, including “Creating and Inserting Elements”, are free to read in full here on the web. After that, CoddyKit PRO unlocks every lesson, plus interactive practice with a built-in code editor and a 24/7 AI tutor. The JavaScript Academy course includes 4 lessons in total.

What will I learn in “Creating and Inserting Elements”?

Build new nodes with createElement and append. You practise JavaScript Academy with hands-on code you run directly in the browser, and a 24/7 AI tutor answers your questions as you work through the lesson.

Do I need any experience to start JavaScript Academy?

No prior experience is required. JavaScript Academy on CoddyKit is structured for beginners through advanced learners, so you can start here or from the beginning and move at your own pace. This is lesson 2 of 4.

How long does the “Creating and Inserting Elements” lesson take?

Most CoddyKit lessons take about 5–10 minutes. Each one is bite-sized and interactive, so you make steady progress and pick up exactly where you left off across the web and the app.

Can I write and run code in this JavaScript Academy lesson?

Yes. Every JavaScript Academy lesson includes a built-in code editor, so you write and run real code right in your browser and get instant AI feedback — no local setup required.

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