component.html

<!doctype html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Vue JS - Component</title>
</head>
<body>

<div id="app">
    {{a}}


    <hyder-component>
        <my-component></my-component>
    </hyder-component>

</div>


<script src="js/vue.min.js"></script>
<script>


    var Child = Vue.extend({
        template: '<div>A custom component! - {{a}} {{message}}</div>',
        data: function(){
            return {a:100}
        }
    })

    // register
    Vue.component('my-component', Child)

    Vue.component('hyder-component', Parent)

    var Parent = Vue.extend({
        template: '<div class="parent-template">This is my parent\'s template</div>',
        components: {
            // <my-component> will only be available in Parent's template
            'my-component': Child
        }
    })


    // create a root instance
    new Vue({
        el: '#app',
        data:{
            message:"Heye"
        }
    })

</script>
<style>
    .error{
        color: red;
    }
</style>
</body>
</html>