JS - Adding a random background to pages with a specific html.classname

Question

I'm adding a script that adds random background images to pages, like so:

<script type="text/javascript">
var totalCount = 25;
function addBackground()
{
  var num = Math.ceil( Math.random() * totalCount );
  document.body.background = 'images/'+num+'.png';
  document.body.style.backgroundSize = "contain";
}
</script>

The complication is, I now need to only add backgrounds to pages that have a specific class (not an id) added to their html element. (I don't have access to change the way this works).

I've tried using getElementsByClassName, but I seem to keep getting Undefined back. What's the correct way to do this?

Thanks!

not sure what you want to achive. :P – X.Creates Feb 23 '17 at 01:51 — X.Creates, Feb 23 '17 at 01:51

score 0 · Answer 1 · edited May 23 '17 at 11:53

0

Get element on page undefined which potentially means when the code get executed the DOM is not ready. If you are not using jQuery check out $(document).ready equivalent without jQuery.

Put your logic into the ready function to make sure the element(s) is rendered at the time your logic run.

edited May 23 '17 at 11:53

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answered Feb 23 '17 at 01:55

X.Creates

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JS - Adding a random background to pages with a specific html.classname

1 Answers1