Adding basic interactivity with directives

Let's add some interactivity to our otherwise quite static app, for example, a text input that will allow the user to change the message displayed. We can do that in templates with special HTML attributes called directives.

All the directives in Vue start with v- and follow the kebab-case syntax. That means you should separate the words with a dash. Remember that HTML attributes are case insensitive (whether they are uppercase or lowercase doesn't matter).

The directive we need here is v-model, which will bind the value of our <input> element with our message data property. Add a new <input> element with the v-model="message" attribute inside the template:

<p id="root">
  <p>{{ message }}</p>
  <!-- New text input -->
  <input v-model="message" />
</p>

Vue will now update the message property automatically when the input value changes. You can play with the content of the input to verify that the text updates as you type and the value in the devtools changes:

There are many more directives available in Vue, and you can even create your own. Don't worry, we will cover that in later chapters.