What does "{%" do in HTML?

Question

I've added Django messages to my app using the official documentation. In it it says to add something like this to my template:

{% if messages %}
<ul class="messages">
    {% for message in messages %}
    <li{% if message.tags %} class="{{ message.tags }}"{% endif %}>{{ message }}</li>
    {% endfor %}
</ul>
{% endif %}

I have no idea what the percentage signs do, they're not actual HTML right?

Answer 1

It's a template engine syntax use in html pages, django compile it when you render a view html with a context variable and return a basic html response.

In your case your message will be your context variable and django engine compile it like :

if message is not None then inner part html is visible.

Doc. Link: https://docs.djangoproject.com/en/1.7/topics/templates/