04-v-if.html

<div id="app">
	<button v-on:click='seen=1'>Show</button>
	<button v-on:click='seen=0'>Hide</button>

	<p v-if="seen">Now you see me</p>

	<form v-on:submit.prevent="onSubmit"></form>
		<input type='text'>
		<br>
		This form will not be submitted
		<br>
		<button type='submit'>Submit</button>
	</form>	
</div>

<script src="https://unpkg.com/vue@2.1.10/dist/vue.js"></script>

<script>
	var vm = new Vue({
		el: '#app',
		data: {
			seen: 1
		}
	})
</script>