<div id="todo-list-example">
        <form v-on:submit.prevent="addNewTodo">
           <label for="new-todo">Add a todo</label>
            <input v-model="newTodoText" id="new-todo" placeholder="E.g. Feed the cat">
            <input type="submit" value="Send Request">
        </form>
        <ul>
            <li is="todo-item" v-for="(todo, index) in todos" 
            	v-bind:key="todo.id" 
            	v-bind:title="todo.title"
                v-on:remove="todos.splice(index, 1)"></li>
        </ul>
    </div>
    <script>
        Vue.component('todo-item', {
            template: '
                    <li>
                    {{ title }}
                    <button v-on:click="$emit('remove')">Remove</button>
                   </li>
                ',    
            props: ['title']
        })

		new Vue({
            el: '#todo-list-example',
            data: {
                newTodoText: '',
                todos: [{
                        id: 1,
                        title: 'Do the dishes',
                    },
                    {
                        id: 2,
                        title: 'Take out the trash',
                    },
                    {
                        id: 3,
                        title: 'Mow the lawn'
                    }
                ],
                nextTodoId: 4
            },
            methods: {
                addNewTodo: function () {
                    this.todos.push({
                        id: this.nextTodoId++,
                        title: this.newTodoText
                    })
                    this.newTodoText = ''
                }
            }
        })
    </script>
    v-on:submit.prevent ==》指在该表单中的任何提交按钮都可以触发该事件