Forms with Events Lab

Build one of the most common applications on the web, a simple todo application, with HTML, CSS, and JavaScript.

---

Lab Setup

1. Fork and clone this repository.

2. Navigate to the settings tab on GitHub, then choose Pages from the menu. Configure the Build and Deployment to have a Source of Deploy from a branch and select the main branch for deployment. Deployments can take a few minutes, so get started on the lab, and then be sure to check the deployment after you have made a few commits.

3. Open up the repository in VSCode. Follow the instructions below to complete the Lab.

Instructions

The app will have the following items:

• An h1 title (e.g. "My To-Dos").
• A single ul tag, empty when the page is first loaded.
• A form for the user to add a new to-do, with a single text input and a submit button.

And the following functionalities:

• When the user writes something in the form's text input area and clicks submit, the ul should update with a new li item at the bottom of the list. The page should not refresh.

  Hints/Steps

  1. Add an event listener to the form with .addEventListener. What event do you want to listen for?
  2. Remember, what does event.preventDefault() do?
  3. Grab the value the user typed from the text input. Do you remember what property of the input node has this? If not Google it or ask a peer.
  4. Create new li element with document.createElement(). Set its textContent property to be the text the user typed.
  5. Don't forget to append the created li to the list.

• When the user writes nothing in the form's text input area and clicks submit, an error message (inside a p tag) should appear below the form.

  Hints/Steps

  1. How can you check if the input text has something typed or not?
  2. Have an empty paragraph that is above the <ul> and under the <form>. If the user didn't type anything, modify the content of the paragraph to display a text like: 'Error. Todo cannot be empty'

• When the user clicks on one of the li items, the item should be crossed out, indicating that that to-do is complete. You will need to look at [element].style.textDecoration for the cross out effect. Look at all the different text decoration options.

  Hints/Steps

  1. You will need to add an event listener to all the li elements. Those li elements have yet to be created. How can you add an event listener to these?
  2. How can you only affect the li that was clicked on?

Sample

Bonus Tasks

• Have the input go back to empty after adding a new todo.
• Implement a delete button next to each li that removes that li tag entirely.
• Clicking a todo that is crossed out (completed) uncrosses the todo.
• Add the ability to add multiple to-dos if the user submits a text input with multiple lines. Each line should be a new to-do.
• Add some CSS styling to your app.