Vue simple thing

 new Vue({
       el: '#app',
        data: {
            counter: 0,
            x: 0,
            y: 0
        },
        methods: {
           increase: function(step){
               this.counter += step;
           },
           updateCoordinates: function(event){
               this.x = event.clientX;
               this.y = event.clientY;
           },
            alertMe: function () {
               alert('Alert');
            }
        }
    })