Advice generator app

Feedback welcome on this completed project, especially on my JavaScript.

The criteria for this project is that it gets a quote on click, I have functionality for both click and every 8 seconds, it will generate a new quote similar to a slideshow of quotes.

I'm curious to know whether the second function can somehow be nested within the setInterval function, the only issue I had was being able to call the setInterval function hence why they are separated now. I'm aware I cannot call 'setInteval' but I also couldn't store it in another variable to do what I desire. Food for through.

Thanks for looking!