# JavaScript入門教學Day19

16th鐵人賽

s1411132022

團隊NUTC_IMAC

2024-09-28 18:01:14

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JavaScript入門教學Day19

Todo list專案總結

程式碼
html部分：

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Todo List</title>
    <link rel="stylesheet" href="style.css">
</head>
<body>
    <h1>Todo List</h1>
    <form id="todo-form">
        <input type="text" id="todo-input" placeholder="新增待辦事項">
        <button type="submit">新增</button>
    </form>
    <ul id="todo-list"></ul>
    <script src="script.js"></script>
</body>
</html>

css部分：

ul {
    list-style-type: none;
    padding: 0;
}

li {
    padding: 10px;
    margin: 5px 0;
    background-color: #f4f4f4;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

li.completed span {
    text-decoration: line-through;
    color: gray;
}

.delete-btn {
    background-color: red;
    color: white;
    border: none;
    padding: 5px 10px;
    cursor: pointer;
}

Javascript部分：

// 選擇元素
const todoForm = document.getElementById("todo-form");
const todoInput = document.getElementById("todo-input");
const todoList = document.getElementById("todo-list");

// 頁面載入時從 localStorage 載入待辦事項
document.addEventListener("DOMContentLoaded", function () {
    const savedTodos = JSON.parse(localStorage.getItem("todos")) || [];
    savedTodos.forEach(todo => addTodoItem(todo.text, todo.completed));
});

// 新增待辦事項
todoForm.addEventListener("submit", function (event) {
    event.preventDefault(); // 防止表單提交
    const todoText = todoInput.value.trim();

    if (todoText !== "") {
        addTodoItem(todoText);
        todoInput.value = ""; // 清空輸入框
    }
});

// 新增待辦事項到列表並保存至 localStorage
function addTodoItem(text, completed = false) {
    const li = document.createElement("li");

    const span = document.createElement("span");
    span.textContent = text;
    li.appendChild(span);

    const deleteBtn = document.createElement("button");
    deleteBtn.textContent = "刪除";
    deleteBtn.classList.add("delete-btn");
    li.appendChild(deleteBtn);

    // 點擊待辦事項標記為完成
    span.addEventListener("click", function () {
        li.classList.toggle("completed");
        saveTodos();
    });

    // 刪除待辦事項
    deleteBtn.addEventListener("click", function () {
        li.remove();
        saveTodos();
    });

    if (completed) {
        li.classList.add("completed");
    }

    todoList.appendChild(li);
    saveTodos();
}

// 儲存待辦事項到 localStorage
function saveTodos() {
    const todos = [];
    document.querySelectorAll("#todo-list li").forEach(li => {
        todos.push({
            text: li.querySelector("span").textContent,
            completed: li.classList.contains("completed")
        });
    });
    localStorage.setItem("todos", JSON.stringify(todos));
}

最終結果

包含了標題、一個輸入框、一個新增鈕

輸入要記錄的待辦事項後按新增

會發現最後面會出現一個紅色的刪除按鈕