Vue关于数据绑定出错解决办法

<input id="input-check" type="checkbox" v-model="toggle" v-bind:true-value="a" v-bind:false-value="b">  <label for="input-check">check</label>  <script type="text/javascript">    var v = new Vue({      el: "#input-check",      data: {        toggle: ""      }    });  </script>

 var v = new Vue({      el: "#input-check",      data: {        toggle: "",        a : "a",        b : "b"      }    });