<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <meta name="viewport" content="width=device-width, initial-scale=1.0"> <meta http-equiv="X-UA-Compatible" content="ie=edge"> <title>Document</title> <script src="./lib/vue-2.4.0.js"></script> </head> <body> <div id="app"> <input type="text" v-model="firstname"> + <input type="text" v-model="middlename"> + <input type="text" v-model="lastname"> = <input type="text" v-model="fullname"> <p>{{ fullname }}</p> <p>{{ fullname }}</p> <p>{{ fullname }}</p> </div> <script> // 创建 Vue 实例，得到 ViewModel var vm = new Vue({ el: '#app', data: { firstname: '', lastname: '', middlename: '' }, methods: {}, computed: { //In computed, you can define a number of properties that called [computing] attribute to calculate the properties of the essence, is a method, but we use these calculations when the property is put their names directly as property to use; will not calculate property, as a way to call; // Note 1: calculation property, when referenced, must not add () to call it directly as a common property to use just fine ; // NOTE: as long as the attribute is calculated, data in any data inside this function, used in the transmission changes, it will immediately recalculates the value of this attribute calculation // NOTE 3: property evaluation result of the calculation, will be cached and used directly for next time; If the calculation method attribute, any of the data, did not change over, then not re-calculated property evaluation; ' FullName ' : function () { the console.log ( ' OK ' ) return the this .firstname + ' - ' + the this .middlename + ' - ' + this.lastname } } }); </script> </body> </html>