Form has a div within it. How can I add classes to this div?

Question

There's a div called .description in a form in the site I've inherited. I want to add a another class to the div.

The div's content is created within hook_form_FORM_ID_alter(), eg:

$form['#description'] = 'Please enter your full name';

I've tried adding a classed to it like:

$form['#description'] = [
    '#markup' => '<div class="my-class">Please enter your full name</div>',
  ];

But this just results in "Array" being printed.

Would anyone know what I could do add a class to this element?

Answer 1

That's not what you want. What you want to do is add it to the form structure like this:

$form['#attributes']['class'][] = 'my-class';

Since you didn't list an element on the form, I can only assume you want the class on the form itself. If you want to wrap an element with a div with a class on it, you can do:

$form['element']['#prefix'] = '<div class="my-class">';
$form['element']['#suffix'] = '</div>';

That will wrap the entire element.