花括号表达式的用法

1、案例1
<!DOCTYPE html>
<html>

<head>
    <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
    <title>花括号表达式</title>
</head>

<body>
    <div id="app">
        <input type="text" v-model="username" />
        <p>Hello{{username}}</p>
        <p>{{msg}}</p>
        <p>{{msg.toUpperCase()}}</p>
    </div>
    <script src="../js/vue.js" type="text/javascript"></script>
    <script>
        const vm = new Vue({
            el: "#app",
            data: {
                username: "liuyang",
                msg: "<a href='http://www.baidu.com'>百度</a>"
            }
        });
    </script>
</body>

</html>
运行结果：