index.html

<!DOCTYPE html>
<html>
<head>
    <title>To-Do List App</title>
    <style>
        body {
            font-family: Arial, sans-serif;
        }
        
        .container {
            max-width: 400px;
            margin: 0 auto;
            padding: 20px;
            border: 1px solid #ccc;
            border-radius: 5px;
        }
        
        h1 {
            text-align: center;
        }
        
        input[type="text"] {
            width: 100%;
            padding: 10px;
            margin-bottom: 10px;
        }
        
        ul {
            list-style-type: none;
            padding-left: 0;
        }
        
        li {
            display: flex;
            align-items: center;
            justify-content: space-between;
            padding: 10px;
            background-color: #f9f9f9;
            margin-bottom: 5px;
        }
        
        li.completed {
          text-decoration: line-through;  
          color:#999999; 
       }
       
       .delete-btn{
           background-color:#ff0000; 
           color:#ffffff; 
           border:none; 
           padding:.5rem .75rem; 
           cursor:pointer; 
           font-size:.8rem; 
           border-radius:.25rem
       }

    </style>
</head>
<body>
    <div class="container">
        <h1>To-Do List</h1>
        <input type="text" id="taskInput" placeholder="Enter a task">
        <ul id="taskList"></ul>
    </div>

    <script>
      // Get the input field and the task list
      const taskInput = document.getElementById("taskInput");
      const taskList = document.getElementById("taskList");

      // Add event listener to the input field
      taskInput.addEventListener("keydown", function(event) {
        if (event.key === "Enter") {
          event.preventDefault();
          addTask();
        }
      });

      // Function to add a new task
      function addTask() {
        const taskText = taskInput.value.trim();

        if (taskText !== "") {
          const li = document.createElement("li");
          li.innerHTML = `
            <span>${taskText}</span>
            <button class="delete-btn">Delete</button>
          `;

          // Add event listener to the delete button
          const deleteBtn = li.querySelector(".delete-btn");
          deleteBtn.addEventListener("click", function() {
            li.remove();
          });

          // Add event listener to mark the task as completed
          li.addEventListener("click", function() {
            li.classList.toggle("completed");
          });

          taskList.appendChild(li);
          
          // Clear the input field
          taskInput.value = "";
        }
      }
    </script>
</body>
</html>