My eventdefault is not working what is the problem

const todoInput = document.querySelector(".todo-input");
const todoButton = document.querySelector(".todo-button");
const todoList = document.querySelector(".todo-list");

// event listner
todoButton.addEventListener("click",addTodo);

function addTodo(event){
  //prevent default
  event.preventDefault();

I’ve edited your post for readability. When you enter a code block into a forum post, please precede it with a separate line of three backticks and follow it with a separate line of three backticks to make it easier to read.

You can also use the “preformatted text” tool in the editor (</>) to add backticks around text.

See this post to find the backtick on your keyboard.
Note: Backticks (`) are not single quotes (’).

What do you mean by “it isn’t working”. You’ve only provided a tiny snippet, so it isn’t really possible to tell what is or isn’t happening. If you could describe in a little more detail and ideally put the code up Codepen or similar that would be great