Edit in JSFiddle

<div id="demo" v-cloak>
    <h1>{{title | uppercase}}</h1>
    <p v-if="!todos.length">No todos at this moment.</p>
    <ul>
        <li v-for="todo in todos"
            :class="{ done: todo.done }"
            @click="todo.done = !todo.done">
            {{ todo.content }}
        </li>
    </ul>
</div>

var demo = new Vue({
    el: '#demo',
    data: {
        title: 'todos',
        todos: [] //testing with data use: [{done:false,content:'testing'}]
    }
})

body {
    font-family: Helvetica Neue, Arial, sans-serif;
}
li.done {
    text-decoration: line-through;
}
[v-cloak] {
    display: none;
}