methods:{
onChange: function(e){
var id = e.target.value;
var name = e.target.options[e.target.options.selectedIndex].text;
console.log('id ',id );
console.log('name ',name );
},
<select name="customerName" id="" v-on:change="onChangeSite($event)">
<option value="1">Jan</option>
<option value="2">Doe</option>
<option value="3">Khan</option>
</select>