Untitled

<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <!-- CDN -->
    <script src="https://unpkg.com/vue"></script>
    <style>
        body {
            background: #20262E;
            padding: 20px;
            font-family: Helvetica;
        }

        #app {
            background: #fff;
            border-radius: 4px;
            padding: 20px;
            transition: all 0.2s;
        }

        li {
            margin: 8px 0;
        }

        h2 {
            font-weight: bold;
            margin-bottom: 15px;
        }

        del {
            color: rgba(0, 0, 0, 0.3);
        }
    </style>
</head>

<body>
    <div id="app">
        <h2>Todos:</h2>
        <ol>
            <li v-for="todo in todos">
                <label>
                    <input type="checkbox" v-on:change="toggle(todo)" v-bind:checked="todo.done">

                    <del v-if="todo.done">
                        {{ todo.text }}
                    </del>
                    <span v-else>
                        {{ todo.text }}
                    </span>
                </label>
            </li>
        </ol>
    </div>
</body>
<script>

    let vm = new Vue({
        el: "#app",
        data: {
            todos: [
                { text: "Learn JavaScript", done: false },
                { text: "Learn Vue", done: false },
                { text: "Play around in JSFiddle", done: true },
                { text: "Build something awesome", done: true }
            ]
        },
        methods: {
            toggle: function (todo) {
                todo.done = !todo.done
            }
        }
    })
</script>

</html>