可以定义一个对象，然后写true或者false

    1.     <body>
    2.         <script type="text/javascript" src="https://unpkg.com/vue/dist/vue.js"></script>
    4.         <div id="app" class="basic" v-bind:class="ysobj" >
    5.             {{ name }}
    6.         </div>
    9.         <script>
    10.                 var vm = new Vue ({
    11.                     data: {
    12.                         name: "hello world",
    13.                         ysobj:{
    14.                             black: false,
    15.                             green: true,
    16.                         }
    17.                     },
    19.                 }); 
    20.                 vm.$mount("#app")
    21.         </script>