How else is done in my case?

Question

MODX

Hello, please give me an idea.
1 - There is a button

<button type="button" class="btn btn-sunny text-uppercase btn-lg"><a href="" target="_blank">ДЕМО</a></button>

How to make if the URL does not enter, then the button was OFF
2 - There is an image

<img src="" class="img-fluid" alt="">

How to do so, if the image is not loaded, then just another picture was displayed (as they do "No image")?

Answer 1

This is what I understand from the picture

<a href="http://askmeplz.com/"><img class="img-fluid" src="/bootstrap/img/profile.png" style="width: 20%;" alt=""></a>