<table class="table table-bg table-border table-bordered"> <tr>  <th>ID</th>  <th>書名</th>  <th>作者</th>  <th>價格</th>  <th>操作</th> </tr> <tr v-for="(book,index) in books">  <td>{{book.id}}</td>  <td>{{book.name}}</td>  <td>{{book.author}}</td>  <td>{{book.price}}</td>  <td>   <button class="btn" @click="delBook(index)">刪除</button>  </td> </tr></table><fieldset> <legend>添加新書</legend> <p>書名：<input type="text" v-model="newBook.name"></p> <p>作者：<input type="text" v-model="newBook.author"></p> <p>價格：<input type="text" v-model="newBook.price"></p> <p><button class="btn" @click="addBook">添加</button></p></fieldset><script>new Vue({ el:'#books', data:{  books:[   {id:1, name:'紅樓夢', author:'曹雪芹', price:'1'},   {id:2, name:'西游記', author:'吳承恩', price:'2'},   {id:3, name:'水滸傳', author:'施耐庵', price:'3'}  ],  newBook:{   id:0,   name:'',   author:'',   price:''  } }, methods:{  delBook:function(idx){   if(window.confirm('確認(rèn)要刪除？')){    this.books.splice(idx, 1);   }  },  addBook:function(){   // 約束   if(this.newBook.name.length == 0) {    alert('書名不能為空');    return;   }    if(this.newBook.author.length == 0){    alert('書的作者不能為空');    return;   }   if(this.newBook.price.length == 0){    this.newBook.price = '0'   }    // 計算插入id   var maxId = 0;   for(var i=0; i<this.books.length; i++){    if(maxId<this.books[i].id){     maxId = this.books[i].id;    }   }   this.newBook.id = maxId+1;   // 插入到 books中   this.books.push(this.newBook);   // 清空新書   this.newBook = {};  } }});</script>