index.html

<!doctype html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport"
          content="width=device-width, user-scalable=no, initial-scale=1.0, maximum-scale=1.0, minimum-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <link  type="text/css" rel="stylesheet" href="./main.css">
    <script src="https://unpkg.com/vue"></script>

    <title>Document</title>
</head>
<body>
<!--vue app是根容器-->
<div id="vue-app">

    <button v-on:click="updatexy">{{x}},{{y}}</button>
</div>
<script src="./app.js"></script>
</body>
</html>

app.js

new Vue({
    el:"#vue-app",
    data:{
        age:18,
        x:0,
        y:0
    },
    methods:{
        updatexy(event){
            this.x=event.offsetX,
                this.y=event.offsetY
        }
    }
})

运行结果