<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <!--Vue安装-->
    <script src="https://cdn.staticfile.org/vue/2.2.2/vue.min.js"></script>
</head>
<body>
<div id="app">
    <input v-model="message">
    <div>{{reMessage}}</div>
</div>
</body>
<script>
    let vue = new Vue({
        el: "#app",
        data: {
            message: "abc"
        },
        //这里是methods不是method
        methods: {},
        computed: {
            reMessage: function () {
                return this.message.split('').reverse().join('')
            }
        }
    });
</script>
</html>