SOURCE

new Vue({
  el: '#app',
  name:'test',
  data() {
      return {
          myInt:123456,
      }
  },
  methods: {
    change () {
      this.$nextTick(function(){
      	this.myInt = this.myInt.toString().replace(/[^\d]/g,'')
      })
    }
  }
})

<div id="app">
  myInt:{{myInt}}
  <br>
  请在下表单中继续输入字符串测试<br>
  <input type='text' v-model="myInt" @input='change'>
</div>