mozilla-release/layout/reftests/css-blending/background-blending-gradient-gradient.html

<!--
     Any copyright is dedicated to the Public Domain.
     http://creativecommons.org/publicdomain/zero/1.0/
-->
<html>
<style>
.reftest {
  width: 200px;
  height: 200px;
  background-size: 100px 100px, 200px 200px;
  background-repeat: no-repeat;
}

.blend {
  background-image: linear-gradient(rgb(0,0,255), rgb(255,0,0)),
                    linear-gradient(rgb(0,0,255), rgb(255,0,0), rgb(0,0,255));
  background-blend-mode: difference;
}

</style>
<div class="reftest blend"></div>
</html>