How to make a random website background with css connection?

Question

css

I found a connection for outputting a random background to the site: goo.gl/55e7Ex , on the site the background is located on top of the site, then it is filled with color, as on https://goo.gl/6E1rbu. So, I want to make a random output of the background with its accompanying color, i.e. for each image its own color. Any ideas how to implement this?

Answer 1

<script>
var backgrounds = [
  "#f00 url(images/backgrounds/img1.jpg) top center",
  "#0f0 url(images/backgrounds/img2.jpg) top center",
  "#00f url(images/backgrounds/img3.jpg) top center"
];
document.body.style.background = backgrounds[Math.floor(Math.random() * (backgrounds.length + 1))];
</script>

Answer 2

class="first_background"
class="second_background"
class="third_background"

etc.