Creating a to-do list application is a great way to learn the basics of JavaScript, including DOM manipulation, event handling, and working with arrays. In this tutorial, we will build a simple to-do list where users can add, delete, and mark tasks as completed.
Build a To-Do List Application with JavaScript, HTML & CSS
Building a To-Do List Application with JavaScript, HTML, and CSS is an excellent project for beginners and intermediate developers because it combines essential skills in front-end web development. This project allows you to practice the foundational concepts of HTML for structure, CSS for styling, and JavaScript for functionality. You learn to manipulate the Document Object Model (DOM), handle user inputs, implement event listeners, and store tasks dynamically. The to-do list application also introduces real-world programming concepts like data persistence using local storage, enhancing usability by saving tasks between sessions. Moreover, the project is highly customizable, giving you the opportunity to improve your design and add advanced features like sorting tasks, adding deadlines, or integrating animations. Overall, it’s a fun and practical way to strengthen your coding skills and create a functional application you can use daily.
Step 1: Setting Up the HTML Structure
The HTML code sets up a simple to-do list interface consisting of three main elements: a text input, a button, and a list display. The text input allows users to type in new tasks, and it includes a placeholder to guide them. The "Add Task" button is used to submit the task, and an unordered list (<ul>) is provided to display the tasks dynamically as list items. These elements are grouped inside a container <div> for better structure and organization. The page is styled for responsiveness with meta tags in the <head> section, ensuring it works well on all devices. Additionally, an external JavaScript file (script.js) is linked to the page, which will handle the logic for adding tasks to the list when the user interacts with the input field and button. This combination of HTML and JavaScript creates the foundation for a functional to-do list application.
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>To-Do List</title>
</head>
<body>
<h1>To-Do List</h1>
<div class="todo-container">
<input type="text" id="todo-input" placeholder="Add a new task...">
<button id="add-todo">Add Task</button>
<ul class="todo-list" id="todo-list"></ul>
</div>
<script src="script.js"></script>
</body>
</html>This code creates the structure of a basic To-Do List web application using HTML. It serves as the "skeleton" of the app where the content and elements will be displayed and later enhanced with functionality using JavaScript. Let’s break it down step by step:
1. HTML Document Setup
<!DOCTYPE html>
<html lang="en"><!DOCTYPE html>: Declares this document is an HTML5 document.
<html lang="en">: Starts the HTML element and declares the language of the content as English.
2. Head Section
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>To-Do List</title>
</head><meta charset="UTF-8">: Sets the character encoding to UTF-8, allowing for all standard characters and symbols to be used.
<meta name="viewport" content="width=device-width, initial-scale=1.0">: Ensures the page is responsive, meaning it adjusts to different screen sizes, especially mobile devices.
<title>To-Do List</title>: Sets the title of the webpage, which appears on the browser tab.
3. Body Section
The body contains everything visible to the user.
Heading
<h1>To-Do List</h1>A main heading (<h1>) displaying "To-Do List" as the title of the application.
To-Do Container
<div class="todo-container">
<input type="text" id="todo-input" placeholder="Add a new task...">
<button id="add-todo">Add Task</button>
<ul class="todo-list" id="todo-list"></ul>
</div>This is the core part of the to-do list interface:
<div class="todo-container">: A container to group the related to-do list elements.
Task Input Field
<input type="text" id="todo-input" placeholder="Add a new task...">type="text": Allows the user to input text.
id="todo-input": Assigns a unique ID to the input field (used later in JavaScript for accessing its value).
placeholder="Add a new task...": Displays a temporary hint text that disappears when the user types.
Add Task Button
<button id="add-todo">Add Task</button>A button labeled "Add Task".
id="add-todo": A unique ID for the button, which will be used to attach an event listener in JavaScript.
To-Do List Display
<ul class="todo-list" id="todo-list"></ul>An unordered list (<ul>) where the tasks will be displayed dynamically as list items (<li>).
id="todo-list": Gives it a unique ID to target it in JavaScript.
4. Script Tag
<script src="script.js"></script>This line links an external JavaScript file (script.js) to the HTML which we will discuss next.
The JavaScript will add interactivity to the to-do list, such as Taking input from the text field, adding a new task to the list when the button is clicked & displaying tasks in the <ul> list dynamically.
Step 2: Writing the JavaScript Code
Create a script.js file and link it to your HTML file. This is where the functionality of the to-do list will be implemented.
Initialize the DOM Elements
Start by selecting the input field, button, and the list.
// Select DOM elements
const todoInput = document.getElementById('todo-input');
const addTodoButton = document.getElementById('add-todo');
const todoList = document.getElementById('todo-list');Add a Task
Write a function to add a new task to the to-do list. This JavaScript function, addTodo, adds a new task to a to-do list when triggered. It first retrieves the task text from an input field (todoInput) and trims any extra whitespace. If the input is empty, it alerts the user to enter a task and exits the function. Otherwise, it creates a new list item (<li>) and sets its text content to the task input. A "Delete" button is also created as a <span> element, styled with a "delete" class, and attached with a click event that removes the corresponding task (li.remove()).
Additionally, a click event is added to the list item itself so that clicking on the task (excluding the delete button) toggles a "completed" class, marking the task as done visually. The delete button and task behavior ensure tasks can be removed or updated seamlessly. Once the list item is fully set up, the delete button is appended to it, and the entire list item is added to the to-do list container (todoList). Finally, the input field is cleared for the next task. An event listener is attached to the "Add Task" button (addTodoButton), so the addTodo function executes whenever the button is clicked. This code efficiently handles task addition, deletion, and completion toggling for a functional to-do list.
function addTodo() {
const taskText = todoInput.value.trim();
if (taskText === '') {
alert('Please enter a task!');
return;
}
// Create list item
const li = document.createElement('li');
// Add task text
li.textContent = taskText;
// Add delete button
const deleteButton = document.createElement('span');
deleteButton.textContent = 'Delete';
deleteButton.classList.add('delete');
deleteButton.onclick = () => li.remove();
// Mark task as complete on click
li.onclick = (e) => {
if (e.target !== deleteButton) {
li.classList.toggle('completed');
}
};
li.appendChild(deleteButton);
todoList.appendChild(li);
// Clear input field
todoInput.value = '';
}
// Add event listener to the button
addTodoButton.addEventListener('click', addTodo);Optional: Add Keyboard Support
Allow the user to press Enter to add a task.
todoInput.addEventListener('keypress', (e) => {
if (e.key === 'Enter') {
addTodo();
}
});Step 3: Adding CSS for Styling
CSS code provides styling for a clean and user-friendly to-do list interface. The body is styled with a light gray background color, no margin, and padding for consistent spacing, while the font is set to a simple and modern sans-serif typeface. The main heading (h1) is centered for a clear title display. The .todo-container class creates a visually appealing container with a white background, rounded corners, and a subtle box shadow, centered on the page with a max-width of 500px for better readability.
The input field inside the container is styled to span the full width, with padding and a light border to make it easy for users to type tasks. The button is given a green background (#28a745), white text, rounded corners, and a hover effect that darkens the green to provide feedback when interacted with. The task list (.todo-list) removes default list styles and organizes tasks with a clean layout. Each list item (li) has padding, a light gray background, and borders, with flexbox ensuring tasks and delete buttons are aligned and spaced neatly.
The .completed class visually marks tasks as done by applying a line-through and gray text color. The "Delete" button, styled with the .delete class, uses a red color and a pointer cursor to make it clear that it’s clickable. Overall, this CSS creates an elegant, responsive, and intuitive to-do list design, balancing functionality with visual appeal.
body {
font-family: Arial, sans-serif;
margin: 0;
padding: 20px;
background-color: #f4f4f4;
}
h1 {
text-align: center;
}
.todo-container {
max-width: 500px;
margin: 20px auto;
padding: 20px;
background: white;
border-radius: 5px;
box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
}
.todo-container input {
width: 100%;
padding: 10px;
margin-bottom: 10px;
border: 1px solid #ddd;
border-radius: 4px;
}
.todo-container button {
width: 100%;
padding: 10px;
background: #28a745;
color: white;
border: none;
border-radius: 4px;
cursor: pointer;
}
.todo-container button:hover {
background: #218838;
}
.todo-list {
list-style: none;
padding: 0;
}
.todo-list li {
padding: 10px;
margin-bottom: 5px;
background: #f8f9fa;
border: 1px solid #ddd;
display: flex;
justify-content: space-between;
align-items: center;
}
.completed {
text-decoration: line-through;
color: gray;
}
.delete {
color: red;
cursor: pointer;
}
Step 4: Test Your Application
Open index.html in your browser.
Type a task in the input field and click "Add Task" or press Enter.
Click on a task to mark it as completed.
Click the "Delete" button to remove a task.
Further Improvements
Here are some ideas to extend this application:
Save Tasks: Use localStorage to save tasks so they persist when the page is reloaded.
Edit Tasks: Add functionality to edit tasks.
Filter Tasks: Add options to filter tasks (e.g., show only completed tasks).
Add Animations: Use CSS animations for adding and removing tasks.
Congratulations! You have successfully built a functional to-do list application with JavaScript.
Conclusion
In conclusion, this combination of HTML, CSS, and JavaScript provides a functional and visually appealing to-do list application. The HTML establishes the structure of the page, the CSS enhances its design with clean and user-friendly styles, and the JavaScript brings interactivity by allowing users to add, delete, and mark tasks as complete. Together, these components create a simple yet effective tool for task management, showcasing how front-end web development technologies work in harmony to deliver an engaging user experience. This project is an excellent example of how fundamental web development skills can be applied to create practical applications.
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