1methods:{
2    onChange: function(e){
3        var id = e.target.value;
4        var name = e.target.options[e.target.options.selectedIndex].text;
5        console.log('id ',id );
6        console.log('name ',name );
7    },
8
9
10 <select name="customerName" id="" v-on:change="onChangeSite($event)">
11         <option value="1">Jan</option>
12         <option value="2">Doe</option>
13         <option value="3">Khan</option>
14   </select>

1methods: {
2    handleChange(e) {
3        if(e.target.options.selectedIndex > -1) {
4            console.log(e.target.options[e.target.options.selectedIndex].dataset.foo)
5        }
6    }
7}