I use:
I would like to check if my placeholder is empty.
{
If you want additional content to be displayed in case the placeholder is empty, use the or argument and an additional {% endplaceholder %} closing tag. Everything between {% placeholder "..." or %} and {% endplaceholder %} is rendered in the event that the placeholder has no plugins or the plugins do not generate any output.
Example:
{% placeholder "content" or %}
There is no content.
{% endplaceholder %}