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  const vm = new Vue({
    el: "#app",
    data: {
      a: "v1",
    },
  })
<div id="app">
  <div class="form-horizontal">
    <div class="form-group">
      <label class="col-md-2 control-label">お支払い方法</label>
      <div class="col-md-10">
        <label class="radio-inline">
          <input type="radio" v-model="a" value="v1">クレジットカード</input></label><label class="radio-inline">
          <input type="radio" v-model="a" value="v2">銀行振り込み</input></label><label class="radio-inline">
          <input type="radio" v-model="a" value="v3">チケット</input></label>
      </div>
    </div>
    <div class="form-group" v-if="a == &#39;v1&#39;">
      <label class="col-md-2 control-label">番号</label>
      <div class="col-sm-10 form-inline">
        <input class="form-control" />
<input class="form-control" type="month" />
      </div>
    </div>
    <div class="form-group" v-if="a == &#39;v2&#39;">
      <label class="col-md-2 control-label">口座</label>
      <div class="col-md-10 form-inline">
        <input class="form-control" />
      </div>
    </div>
    <div class="form-group" v-if="a == &#39;v3&#39;">
      <label class="col-md-2 control-label">コード</label>
      <div class="col-md-10 form-inline">
        <input class="form-control" size="8" />
      </div>
    </div>
  </div>
</div>