<!DOCTYPE html>
<link rel="help" href="https://drafts.csswg.org/css-backgrounds-3/#background-color">
<iframe id="foo"></iframe>
<div id="bar"></div>
<script>
$ = document.querySelector.bind(document);
var target = document.getElementById("bar");
target.animate([{"backgroundColor":"blue"},{"backgroundColor":"green"}], {"duration":10});
$('iframe').contentDocument.documentElement.appendChild(target);
$('#foo').remove();
</script>