Vue Js Radio Button Validation

<html>

</head>

<body>
    <div id="app">
        <h3>Vue Js Radio Button Validation</h3>
        <p>Show Alert if Radio Button is not Selected</p>

<form @submit.prevent="validateForm">
            <label>Select Option:</label>
                <div v-for='(option,index) in options'>
                    <input type="radio"  :id="index" v-model="selectedValue" :value="option">{{option}}
                </div>
                <br><br>
                <button type="submit" @click="validateForm">submit</button>
        </form>
       <pre>Get Selected Value: {{selectedValue}}</pre>
    </div>