Using event modifier .prevent in Vue to submit form without redirection

Just use @submit.prevent (without any equal signs).

Then, define @click="doAction()" on the button.

onSubmit should be a function within your methods property on the vue instance. I.e

methods: {
  onSubmit () {
    // DO Something
  }
}

Then as the docs say, using <form v-on:submit.prevent="onSubmit"></form> is correct. I use this in my app.

See the example below. The message will change once the button is clicked without a page refresh.

var vm = new Vue({
  el: '#app',
  data () {
    return {
      test: 'BEFORE SUBMIT'
    }
  },
  methods: {
    onSubmit () {
      this.test = 'AFTER SUBMIT'
    }
  }
});

<script src="https://unpkg.com/vue/dist/vue.js"></script>
<div id="app">
  {{test}}
  <form v-on:submit.prevent="onSubmit">
    <button>Submit!</button>
  </form>
</div>