## Exercise

### Update Navigation

1. Add an onclick attribute to all 3 buttons in the navigation.
2. For each onclick call the `filter` function. In our function we need a reference to the clicked button, so pass in the keyword `this` as the only parameter.

### Write updateRemaining function

1. Get a reference to the span with the `remaining` class, and store it in a variable.
2. Use [querySelectorAll](https://developer.mozilla.org/en-US/docs/Web/API/Document/querySelectorAll) to get all of the todos.
3. Set the `innerText` of the remaining span to the length of those todos.
4. Add updateRemaining() to end of addTodo function.

### Write a clearCompleted function

1. Get a reference to all of the todos with [querySelectorAll](https://developer.mozilla.org/en-US/docs/Web/API/Document/querySelectorAll).
2. Use a `for (let todo of todos)` loop to iterate over each todo.
3. Inside the for loop write an `if` statement to test if the `input` inside of the todo has a checked value of true.
   > Hint: you can use querySelector on any HTML node to find child elements within.
4. Call `todo.remove()` for any todo whos input check is true.
5. After the loop is done, run `updateRemaining()`.
6. Attach this function to the footer button.
7. Test it out!